Monthly trending articles on ConnectClue
When is the @JsonProperty property used and what is it used for?
Here's a good example. I use it to rename the variable because the JSON is coming from a
.Net environment where properties start with an upper-case letter.public class Parameter {
@JsonProperty("Name")
public String name;
@JsonProperty("Value")
public String value;
}
This correctly parses to/from the JSON:
"Parameter":{
"Name":"Parameter-Name",
"Value":"Parameter-Value"
}
Post updated on: Feb 20, 2023 1:13:27 AM
What is REST API error handling best practices?
I wouldn't return a 200 unless there really was nothing wrong with the request. From RFC2616, 200 means "the request has succeeded."
If the client's storage quota has been exceeded (for whatever reason), I'd return a 403 (Forbidden):
This tells the client that the request was OK, but that it failed (something a 200 doesn't do). This also gives you the opportunity to explain the problem (and its solution) in the response body.
What other specific error conditions?
The main choice is done you want to treat the HTTP status code as part of your REST API or not.
Both ways work fine. I agree that strictly speaking, one of the ideas of REST is that you should use the HTTP Status code as a part of your API (return 200 or 201 for a successful operation and a 4xx or 5xx depending on various error cases.) However, there is no REST police. You can do what you want. I have seen far more egregious non-REST APIs being called "RESTful."
At this point (August 2015) I do recommend that you use the HTTP Status code as part of your API. It is now much easier to see the return code when using frameworks than it was in the past. In particular, it is now easier to see the non-200 return case and the body of non-200 responses than it was in the past.
The HTTP Status code is part of your API
- You will need to carefully pick 4xx codes that fit your error conditions. You can include a rest, XML, or plaintext message as the payload that includes a sub-code and a descriptive comment.
- The clients will need to use a software framework that enables them to get to the HTTP-level status code. Usually doable, not always straightforward.
- The clients will have to distinguish between HTTP status codes that indicate a communications error and your own status codes that indicate an application-level issue.
- The HTTP Status code is NOT part of your API
- The HTTP status code will always be 200 if your app received the request and then responded (both success and error cases)
- All of your responses should include "envelope" or "header" information. Typically something like:
envelope_ver: 1.0 status: # use any codes you like. Reserve a code for success. msg: "ok" # A human string that reflects the code. Useful for debugging. data: ... # The data of the response, if any.
- This method can be easier for clients since the status for the response is always in the same place (no sub-codes needed), no limits on the codes, and no need to fetch the HTTP-level status code.
Main issues:
- Be sure to include version numbers so you can later change the semantics of the api if needed.
- Document
Do remember that 5xx errors are server-side, aka the client cannot change anything to its request to make the request pass. If the client's quota is exceeded, that's definitely not a server error, so 5xx should be avoided.
This is extremely late to the party, but now, in the year 2013, we have a few media types to cover error handling in a common distributed (RESTful) fashion. See "vnd.error", application/vnd.error+json (https://github.com/blongden/vnd.error) and "Problem Details for HTTP APIs", application/problem+json (https://datatracker.ietf.org/doc/html/draft-nottingham-http-problem-05).
There are two sorts of errors. Application errors and HTTP errors. The HTTP errors are just to let your AJAX handler know that things went fine and should not be used for anything else.
5xx Server Error
500 Internal Server Error
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Gateway Timeout
505 HTTP Version Not Supported
506 Variant Also Negotiates (RFC 2295 )
507 Insufficient Storage (WebDAV) (RFC 4918 )
509 Bandwidth Limit Exceeded (Apache bw/limited extension)
510 Not Extended (RFC 2774 )
2xx Success
200 OK
201 Created
202 Accepted
203 Non-Authoritative Information (since HTTP/1.1)
204 No Content
205 Reset Content
206 Partial Content
207 Multi-Status (WebDAV)
However, how you design your application errors is really up to you. Stack Overflow for example sends out an object with
response, data and message properties. The response I believe contains true or false to indicate if the operation was successful (usually for write operations). The data contains the payload (usually for read operations) and the message contains any additional metadata or useful messages (such as error messages when the response is false).Agreed. The basic philosophy of REST is to use the web infrastructure. The HTTP Status codes are the messaging framework that allows parties to communicate with each other without increasing the HTTP payload. They are already established universal codes conveying the status of the response, and therefore, to be truly RESTful, the applications must use this framework to communicate the response status.
Sending an error response in an HTTP 200 envelope is misleading, and forces the client (API consumer) to parse the message, most likely in a non-standard, or proprietary way. This is also not efficient - you will force your clients to parse the HTTP payload every single time to understand the "real" response status. This increases processing, adds latency, and creates an environment for the client to make mistakes.
Don't forget the 5xx errors as well for application errors.
In this case what about 409 (Conflict)? This assumes that the user can fix the problem by deleting stored resources.
Otherwise, 507 (not entirely standard) may also work. I wouldn't use 200 unless you use 200 for errors in general.
If the client quota is exceeded it is a server error, avoid 5xx in this instance.
Post updated on: Feb 20, 2023 1:12:58 AM
hardcode string vs @string in Java code - Android
Using multiple strings of the same value no matter the method (Strings.xml vs programmatically) doesn't seem to have any associated overhead. According to Oracle "All literal strings and string-valued constant expressions are interned" which means that the object is reused rather than re-created if you use it again.
That way you have a fixed place to alter all your strings within the project. Let us say you used the same string in 10 different locations in the code. What if you decide to alter it? Instead of searching for where all it has been used in the project you just change it once and changes are reflected everywhere in the project.
Well, strings.xml would have to be parsed, wouldn't it? Then I suppose hardcoded would be best for performance, though probably unnoticeable at runtime. People do choose to use it though in order to have all the strings in one spot in case there are plans to translate the app.
There are many benefits to setting the strings in a strings.xml file; in a nutshell, it allows you to use the same string in multiple locations, which is good if you somehow need to modify the string later. It also allows you to display the same text in different languages; hardcoding the string doesn't give you all those options.
BTW, you don't need to put every text in the strings.XML file; only the ones that might be used in multiple places in the application.
The general rule for placing strings in the strings.xml file are these:
BTW, you don't need to put every text in the strings.XML file; only the ones that might be used in multiple places in the application.
The general rule for placing strings in the strings.xml file are these:
- Will it be used in multiple locations
- Will it be used in multiple languages
- Will it be dynamic or static
Post updated on: Feb 20, 2023 1:12:38 AM
how to replace "(double quotes) in a string with \" in java
Example -
How do I retrieve query parameters in a Spring Boot controller?
Use @RequestParam
Example -
str = str.replace("\"", "\\\"")
Avoid using replaceAll since it uses regex syntax in description of what to replace and how to replace, which means that \ will have to be escaped in string "\\" but also in regex \\ (needs to be written as "\\\\" string) which means that we would need to use.
str = str.replaceAll("\"", "\\\\\"");
str = str.replaceAll("\"", Matcher.quoteReplacement("\\\""))
How do I retrieve query parameters in a Spring Boot controller?
Use @RequestParam
@RequestMapping(value="user", method = RequestMethod.GET)
public @ResponseBody Item getItem(@RequestParam("data") String empId){
Emp i = empDao.findOne(empId);
String EmpName = i.getEmpName();
String dept= i.getDept();
return i;
}Storing a new object as the value of a hashmap?
HashMap mapper = new HashMap();
mapper.put("Satya", new Emp("Satya"));
...
Emp value = mapper.get("Satya");
Integer memory = value.getMemory();
Post updated on: Feb 20, 2023 1:12:06 AM
How do I add headers for requests from an API?
The sample code:
// Example POST method implementation:
async function postData(url = '', data = {}) {
// Default options are marked with *
const response = await fetch(url, {
method: 'POST', // *GET, POST, PUT, DELETE, etc.
mode: 'cors', // no-cors, *cors, same-origin
cache: 'no-cache', // *default, no-cache, reload, force-cache, only-if-cached
credentials: 'same-origin', // include, *same-origin, omit
headers: {
'Content-Type': 'application/json'
},
redirect: 'follow', // manual, *follow, error
referrerPolicy: 'no-referrer', // no-referrer
body: JSON.stringify(data) // body data type must match "Content-Type" header
});
return await response.json(); // parses JSON response into native JavaScript objects
}
postData('https://example.com/answer', { answer: 08 })
.then((data) => {
console.log(data); // JSON data parsed by `response.json()` call
});
implementation based on the code above:
fetch(url, {
headers: {
"User-Agent": "MyAppName/Version# (Language=Javascript; Platform: Linux)"
}
}).then(function(resp) {
return resp.json();
}).then(function(data){...
Post updated on: Feb 20, 2023 1:11:29 AM
Java Variables - A variable is a container that holds the value while the Java program is executed. A variable is assigned with a data type. The variable is the name of a memory location.
A variable is the name of a reserved area allocated in memory. In other words, it is the name of the memory location. It is a combination of "vary + able" which means
its value can be changed.
Types of Variables
There are three types of variables in Java:
local variable
instance variable
static variable
1) Local Variable
A variable declared inside the body of the method is called local variable. You can use this variable only within that method and the other methods in the class
aren't even aware that the variable exists.
A local variable cannot be defined with "static" keyword.
2) Instance Variable
A variable declared inside the class but outside the body of the method, is called an instance variable. It is not declared as static.
It is called an instance variable because its value is instance-specific and is not shared among instances.
3) Static variable
A variable that is declared as static is called a static variable. It cannot be local. You can create a single copy of the static variable and share it among all
the instances of the class. Memory allocation for static variables happens only once when the class is loaded in the memory.
Example
public class A
{
static int x=10; //static variable
void method()
{
int y=20; //local variable
}
public static void main(String args[])
{
int data=100;//instance variable
}
Java Variable Example: Add Two Numbers
public class Simple{
public static void main(String[] args){
int a=10;
int b=10;
int c=a+b;
System.out.println(c);
}
}
Post updated on: Feb 20, 2023 1:05:44 AM
Operators in Java - is a symbol that is used to perform operations. For example: +, -, *, / etc.
There are many types of operators in Java which are given below:
Unary Operator,
Arithmetic Operator,
Shift Operator,
Relational Operator,
Bitwise Operator,
Logical Operator,
Ternary Operator and
Assignment Operator.
Java Operator Precedence
Operator Type Category Precedence
Unary postfix expr++ expr--
prefix ++expr --expr +expr -expr ~ !
Arithmetic multiplicative * / %
additive + -
Shift shift << >> >>>
Relational comparison < > <= >= instanceof
equality == !=
Bitwise bitwise AND &
bitwise exclusive OR ^
bitwise inclusive OR |
Logical logical AND &&
logical OR ||
Ternary ternary ? :
Assignment assignment = += -= *= /= %= &= ^= |= <<= >>= >>>=
Java Unary Operator
The Java unary operators require only one operand. Unary operators are used to perform various operations i.e.:
incrementing/decrementing a value by one
negating an expression
inverting the value of a boolean
Java Unary Operator Example: ++ and --
public class OperatorExample{
public static void main(String args[]){
int x=10;
System.out.println(x++);//10 (11)
System.out.println(++x);//12
System.out.println(x--);//12 (11)
System.out.println(--x);//10
}}
Java Unary Operator Example 2: ++ and --
public class OperatorExample{
public static void main(String args[]){
int a=10;
int b=10;
System.out.println(a++ + ++a);//10+12=22
System.out.println(b++ + b++);//10+11=21
}}
Java Unary Operator Example: ~ and !
public class OperatorExample{
public static void main(String args[]){
int a=10;
int b=-10;
boolean c=true;
boolean d=false;
System.out.println(~a);//-11 (minus of total positive value which starts from 0)
System.out.println(~b);//9 (positive of total minus, positive starts from 0)
System.out.println(!c);//false (opposite of boolean value)
System.out.println(!d);//true
}}
Java Arithmetic Operators
Java arithmetic operators are used to perform addition, subtraction, multiplication, and division. They act as basic mathematical operations.
Java Arithmetic Operator Example
public class OperatorExample{
public static void main(String args[]){
int a=10;
int b=5;
System.out.println(a+b);//15
System.out.println(a-b);//5
System.out.println(a*b);//50
System.out.println(a/b);//2
System.out.println(a%b);//0
}}
Java Arithmetic Operator Example: Expression
public class OperatorExample{
public static void main(String args[]){
System.out.println(10*10/5+3-1*4/2); //21
}}
Java Left Shift Operator
The Java left shift operator << is used to shift all of the bits in a value to the left side of a specified number of times.
Java Left Shift Operator Example
public class OperatorExample{
public static void main(String args[]){
System.out.println(10<<2);//10*2^2=10*4=40
System.out.println(10<<3);//10*2^3=10*8=80
System.out.println(20<<2);//20*2^2=20*4=80
System.out.println(15<<4);//15*2^4=15*16=240
}}
Java Right Shift Operator
The Java right shift operator >> is used to move the value of the left operand to right by the number of bits specified by the right operand.
Java Right Shift Operator Example
public OperatorExample{
public static void main(String args[]){
System.out.println(10>>2);//10/2^2=10/4=2 //2
System.out.println(20>>2);//20/2^2=20/4=5 //5
System.out.println(20>>3);//20/2^3=20/8=2 //2
}}
Java Shift Operator Example: >> vs >>>
public class OperatorExample{
public static void main(String args[]){
//For positive number, >> and >>> works same
System.out.println(20>>2); //5
System.out.println(20>>>2); //5
//For negative number, >>> changes parity bit (MSB) to 0
System.out.println(-20>>2); //-5
System.out.println(-20>>>2); // 1073741819
}}
Java AND Operator Example: Logical && and Bitwise &
The logical && operator doesn't check the second condition if the first condition is false. It checks the second condition only if the first one is true.
The bitwise & operator always checks both conditions whether first condition is true or false.
public class OperatorExample{
public static void main(String args[]){
int a=10;
int b=5;
int c=20;
System.out.println(a
System.out.println(a
}}
Java AND Operator Example: Logical && vs Bitwise &
public class OperatorExample{
public static void main(String args[]){
int a=10;
int b=5;
int c=20;
System.out.println(a
System.out.println(a);//10 because second condition is not checked //10
System.out.println(a
System.out.println(a);//11 because second condition is checked //11
}}
Java OR Operator Example: Logical || and Bitwise |
The logical || operator doesn't check the second condition if the first condition is true. It checks the second condition only if the first one is false.
The bitwise | operator always checks both conditions whether first condition is true or false.
public class OperatorExample{
public static void main(String args[]){
int a=10;
int b=5;
int c=20;
System.out.println(a>b||a
System.out.println(a>b|a
//|| vs |
System.out.println(a>b||a++
System.out.println(a);//10 because second condition is not checked //10
System.out.println(a>b|a++
System.out.println(a);//11 because second condition is checked //11
}}
Java Ternary Operator
Java Ternary operator is used as one line replacement for if-then-else statements and is used a lot in Java programming. It is the only conditional operator which takes
three operands.
Java Ternary Operator Example
public class OperatorExample{
public static void main(String args[]){
int a=2;
int b=5;
int min=(a
System.out.println(min); //2
}}
Java Assignment Operator
Java assignment operator is one of the most common operators. It is used to assign the value on its right to the operand on its left.
Java Assignment Operator Example
public class OperatorExample{
public static void main(String args[]){
int a=10;
int b=20;
a+=4;//a=a+4 (a=10+4)
b-=4;//b=b-4 (b=20-4)
System.out.println(a); //14
System.out.println(b); //16
}}
Java Assignment Operator Example
public class OperatorExample{
public static void main(String[] args){
int a=10;
a+=3;//10+3
System.out.println(a); //13
a-=4;//13-4
System.out.println(a); //9
a*=2;//9*2
System.out.println(a); //18
a/=2;//18/2
System.out.println(a); //9
}}
Java Assignment Operator Example: Adding short
public class OperatorExample{
public static void main(String args[]){
short a=10;
short b=10;
//a+=b;//a=a+b internally so fine
a=a+b;//Compile time error because 10+10=20 now int
System.out.println(a); // compile time error
}}
After type cast:
public class OperatorExample{
public static void main(String args[]){
short a=10;
short b=10;
a=(short)(a+b);//20 which is int now converted to short
System.out.println(a); // 20
}}
Post updated on: Feb 20, 2023 1:05:12 AM
Java Keywords
Java keywords are also known as reserved words. Keywords are particular words that act as a key to a code. These are predefined words by Java so they cannot be
used as a variable or object name or class name.
List of Java Keywords
A list of Java keywords or reserved words are given below:
abstract: Java abstract keyword is used to declare an abstract class. An abstract class can provide the implementation of the interface. It can have abstract and
non-abstract methods.
boolean: Java boolean keyword is used to declare a variable as a boolean type. It can hold True and False values only.
break: Java break keyword is used to break the loop or switch statement. It breaks the current flow of the program at specified conditions.
byte: Java byte keyword is used to declare a variable that can hold 8-bit data values.
case: Java case keyword is used with the switch statements to mark blocks of text.
catch: Java catch keyword is used to catch the exceptions generated by try statements. It must be used after the try block only.
char: Java char keyword is used to declare a variable that can hold unsigned 16-bit Unicode characters.
class: Java class keyword is used to declare a class.
continue: Java continue keyword is used to continue the loop. It continues the current flow of the program and skips the remaining code at the specified condition.
default: Java default keyword is used to specify the default block of code in a switch statement.
do: Java do keyword is used in the control statement to declare a loop. It can iterate a part of the program several times.
double: Java double keyword is used to declare a variable that can hold a 64-bit floating-point number.
else: Java else keyword is used to indicate the alternative branches in an if statement.
enum: Java enum keyword is used to define a fixed set of constants. Enum constructors are always private or default.
extends: Java extends keyword is used to indicate that a class is derived from another class or interface.
final: Java final keyword is used to indicate that a variable holds a constant value. It is used with a variable. It is used to restrict the user from updating the
value of the variable.
finally: Java finally keyword indicates a block of code in a try-catch structure. This block is always executed whether an exception is handled or not.
float: Java float keyword is used to declare a variable that can hold a 32-bit floating-point number.
for: Java for a keyword is used to start a for loop. It is used to execute a set of instructions/functions repeatedly when some condition becomes true. If the number
of iteration is fixed, it is recommended to use for loop.
if: Java if keyword tests the condition. It executes the if block if the condition is true.
implements: Java implements keyword is used to implement an interface.
import: Java import keyword makes classes and interfaces available and accessible to the current source code.
instanceof: Java instanceof keyword is used to test whether the object is an instance of the specified class or implements an interface.
int: Java int keyword is used to declare a variable that can hold a 32-bit signed integer.
interface: Java interface keyword is used to declare an interface. It can have only abstract methods.
long: Java long keyword is used to declare a variable that can hold a 64-bit integer.
native: Java native keyword is used to specify that a method is implemented in native code using JNI (Java Native Interface).
new: Java new keyword is used to create new objects.
null: Java null keyword is used to indicate that a reference does not refer to anything. It removes the garbage value.
package: Java package keyword is used to declare a Java package that includes the classes.
private: Java private keyword is an access modifier. It is used to indicate that a method or variable may be accessed only in the class in which it is declared.
protected: Java protected keyword is an access modifier. It can be accessible within the package and outside the package but through inheritance only. It can't be
applied with the class.
public: Java public keyword is an access modifier. It is used to indicate that an item is accessible anywhere. It has the widest scope among all other modifiers.
return: Java return keyword is used to return from a method when its execution is complete.
short: Java short keyword is used to declare a variable that can hold a 16-bit integer.
static: Java static keyword is used to indicate that a variable or method is a class method. The static keyword in Java is mainly used for memory management.
strictfp: Java strictfp is used to restrict the floating-point calculations to ensure portability.
super: Java super keyword is a reference variable that is used to refer to parent class objects. It can be used to invoke the immediate parent class method.
switch: The Java switch keyword contains a switch statement that executes code based on test value. The switch statement tests the equality of a variable against
multiple values.
synchronized: Java synchronized keyword is used to specify the critical sections or methods in multithreaded code.
this: Java this keyword can be used to refer to the current object in a method or constructor.
throw: The Java throw keyword is used to explicitly throw an exception. The throw keyword is mainly used to throw custom exceptions. It is followed by an instance.
throws: The Java throws keyword is used to declare an exception. Checked exceptions can be propagated with throws.
transient: Java transient keyword is used in serialization. If you define any data member as transient, it will not be serialized.
try: Java try keyword is used to start a block of code that will be tested for exceptions. The try block must be followed by either catch or finally block.
void: Java void keyword is used to specify that a method does not have a return value.
volatile: Java volatile keyword is used to indicate that a variable may change asynchronously.
while: Java while keyword is used to start a while loop. This loop iterates a part of the program several times. If the number of iterations is not fixed, it is
recommended using the while loop.
Post updated on: Feb 20, 2023 1:04:53 AM
Features of Java
These are the most important features of the Java language is given below.
1. Simple
2. Object-Oriented
3. Portable
4. Platform independent
5. Secured
6. Robust
7. Architecture Neutral
8. Interpreted
9. High Performance
10. Multithreaded
11. Distributed
12. Dynamic
Simple
According to Sun Microsystem, Java language is a simple programming language because:
Java is very easy to learn, and its syntax is simple, clean, and easy to understand.
Java syntax is based on C++ (so easier for programmers to learn it after C++).
Java has removed many complicated and rarely-used features, for example, explicit pointers, operator overloading, etc.
There is no need to remove unreferenced objects because there is an Automatic Garbage Collection in Java.
Object-oriented
Java is an object-oriented programming language. Everything in Java is an object.
Object-oriented means we organize our software as a combination of different types of objects that incorporate both data and behavior.
Object-oriented programming (OOPs) is a methodology that simplifies software development and maintenance by providing some rules.
The basic concepts of OOPs are:
Object
Class
Inheritance
Polymorphism
Abstraction
Encapsulation
Portable
Java is portable because it facilitates you to carry the Java bytecode to any platform. It doesn't require any implementation.
Platform Independent
Java is platform independent
Java is platform-independent because it is different from other languages like C, C++, etc. which are compiled into platform-specific machines while Java is a
write-once, run-anywhere language. A platform is the hardware or software environment in which a program runs.
There are two types of platforms software-based and hardware-based. Java provides a software-based platform.
The Java platform differs from most other platforms in the sense that it is a software-based platform that runs on top of other hardware-based platforms.
It has two components:
Runtime Environment
API(Application Programming Interface)
Java code can be executed on multiple platforms, for example, Windows, Linux, Sun Solaris, Mac/OS, etc. Java code is compiled by the compiler and converted into
bytecode. This bytecode is a platform-independent code because it can be run on multiple platforms, i.e., Write Once and Run Anywhere (WORA).
Secured
Java is best known for its security. With Java, we can develop virus-free systems. Java is secured because:
No explicit pointer
Java Programs run inside a virtual machine sandbox
Classloader: Classloader in Java is a part of the Java Runtime Environment (JRE) which is used to load Java classes into the Java Virtual Machine dynamically.
It adds security by separating the package for the classes of the local file system from those that are imported from network sources.
Bytecode Verifier: It checks the code fragments for illegal code that can violate access rights to objects.
Security Manager: It determines what resources a class can access such as reading and writing to the local disk.
Java language provides these securities by default. Some security can also be provided by an application developer explicitly through SSL, JAAS, Cryptography, etc.
Robust
Java is robust because:
It uses strong memory management.
There is a lack of pointers that avoids security problems.
Java provides automatic garbage collection which runs on the Java Virtual Machine to get rid of objects which are not being used by a Java application anymore.
There are exception-handling and the type checking mechanism in Java. All these points make Java robust.
Architecture-neutral
Java is architecture neutral because there are no implementation-dependent features, for example, the size of primitive types is fixed.
In C programming, the int data type occupies 2 bytes of memory for 32-bit architecture and 4 bytes of memory for 64-bit architecture. However, it occupies 4 bytes
of memory for both 32 and 64-bit architectures in Java.
High-performance
Java is faster than other traditional interpreted programming languages because Java bytecode is "close" to native code. It is still a little bit slower
than a compiled language (e.g., C++).
Java is an interpreted language which is why it is slower than compiled languages, e.g., C, C++, etc.
Distributed
Java is distributed because it facilitates users to create distributed applications in Java. RMI and EJB are used for creating distributed applications.
This feature of Java makes us able to access files by calling the methods from any machine on the internet.
Multi-threaded
A thread is like a separate program, executing concurrently. We can write Java programs that deal with many tasks at once by defining multiple threads.
The main advantage of multi-threading is that it doesn't occupy memory for each thread. It shares a common memory area. Threads are important for multi-media, Web applications, etc.
Dynamic
Java is a dynamic language. It supports the dynamic loading of classes. It means classes are loaded on demand. It also supports functions from its native
languages, i.e., C and C++.
Post updated on: Feb 20, 2023 1:04:00 AM
Data Types in Java
Data types specify the different sizes and values that can be stored in the variable. There are two types of data types in Java: primitive and non-primitive.
Primitive data types: The primitive data types include boolean, char, byte, short, int, long, float, and double.
Non-primitive data types: The non-primitive data types include Classes, Interfaces, and Arrays.
Java Primitive Data Type - In Java language, primitive data types are the building blocks of data manipulation. These are the most basic data types available in Java language.
There are 8 types of primitive data types:
Boolean data type
byte data type
char data type
short data type
int data type
long data type
float data type
double data type
Data Type Default size
boolean 1 bit
char 2 byte
byte 1 byte
short 2 byte
int 4 byte
long 8 byte
float 4 byte
double 8 byte
Boolean Data Type
The Boolean data type is used to store only two possible values: true and false. This data type is used for simple flags that track true/false conditions.
The Boolean data type specifies one bit of information, but its "size" can't be defined precisely.
Example:
Boolean one = false
Byte Data Type
The byte data type is an example of a primitive data type. It is an 8-bit signed two's complement integer. Its value range lies between -128 to 127 (inclusive). Its minimum value is -128 and the maximum value is 127. Its default value is 0.
The byte data type is used to save memory in large arrays where memory savings is most required. It saves space because a byte is 4 times smaller than an integer. It can also be used in place of the "int" data type.
Example:
byte a = 10, byte b = -20
Short Data Type
The short data type is a 16-bit signed two's complement integer. Its value range lies between -32,768 to 32,767 (inclusive). Its minimum value is -32,768 and its maximum value is 32,767. Its default value is 0.
The short data type can also be used to save memory just like the byte data type. A short data type is 2 times smaller than an integer.
Example:
short s = 10000, short r = -5000
Int Data Type
The int data type is a 32-bit signed two's complement integer. Its value range lies between - 2,147,483,648 (-2^31) to 2,147,483,647 (2^31 -1) (inclusive). Its minimum value is - 2,147,483,648and maximum value is 2,147,483,647. Its default value is 0.
The int data type is generally used as a default data type for integral values unless there is no problem with memory.
Example:
int a = 100000, int b = -200000
Long Data Type
The long data type is a 64-bit two's complement integer. Its value-range lies between -9,223,372,036,854,775,808(-2^63) to 9,223,372,036,854,775,807(2^63 -1)(inclusive). Its minimum value is - 9,223,372,036,854,775,808and maximum value is 9,223,372,036,854,775,807. Its default value is 0. The long data type is used when you need a range of values more than those provided by int.
Example:
long a = 100000L, long b = -200000L
Float Data Type
The float data type is a single-precision 32-bit IEEE 754 floating point. Its value range is unlimited. It is recommended to use a float (instead of a double) if you need to save memory in large arrays of floating point numbers. The float data type should never be used for precise values, such as currency. Its default value is 0.0F.
Example:
float f1 = 234.5f
Double Data Type
The double data type is a double-precision 64-bit IEEE 754 floating point. Its value range is unlimited. The double data type is generally used for decimal values just like float. The double data type also should never be used for precise values, such as currency. Its default value is 0.0d.
Example:
double d1 = 12.3
Char Data Type
The char data type is a single 16-bit Unicode character. Its value range lies between '\u0000' (or 0) to '\uffff' (or 65,535 inclusive). The char data type is used to store characters.
Example:
char letterA = 'A'
Post updated on: Feb 20, 2023 1:03:19 AM
If you are a writer and struggling to monetize your work, you have found your solution. If you are a business and want to business to increase by manifolds, you are at the right place too. At ConnectClue, are your 1 solution for everything you are struggling with. You are bound to touch every height you have ever imagined if you are here with us. ConnectClue is a website that provides various services through the medium of Blog and Article Writing. They make sure that your efforts don't go to waste and that every Blog that you write, creative or Business related, reaches the right audience and helps you earn along with being known to a crowd you have only dreamt about yet. Yes, that's right. They are here to make all your dreams come true.
With this comes a question, How? and What is there for us in this?
They understand the struggle and competition of today's market and the gap that has come between the audience and the service providers. At ConnectClue, trying to bridge the same Gap through the medium of writing. Now, how you ask? It's pretty simple. Just make good quality content and start blogging with us here. They make sure that your content reaches as far as possible and they have a viewership from all around the world. Also, help us to earn through your blogs according to the viewership that you get so that our efforts are rewarded right there. Not just us, also provide free Ads, sponsorships, free business marketing, and a lot more.
Post updated on: Jan 28, 2023 1:29:03 PM
What is Java - Java is a high-level, robust, object-oriented, and secure programming language.
Java was developed by Sun Microsystems (which is now a subsidiary of Oracle) in the year 1995. James Gosling is known as the father of Java. Before Java, its name was Oak. Since Oak was already a registered company, so James Gosling and his team changed the name from Oak to Java.
Platform: Any hardware or software environment in which a program runs, is known as a platform. Since Java has a runtime environment (JRE) and API, it is called a platform.
Java Example
Let's have a quick look at the Java programming example.
Example.java
class Example{
public static void main(String args[]){
System.out.println("Hello Java");
}
}
To compile:
javac Example.java
To execute:
Java Example
Parameters used in First Java Program
Let's see what is the meaning of class, public, static, void, main, String[], System.out.println().
The class keyword is used to declare a class in Java.
The public keyword is an access modifier that represents visibility. It means it is visible to all.
static is a keyword. If we declare any method as static, it is known as the static method. The core advantage of the static method is that there is no need to create an object to invoke the static method. The main() method is executed by the JVM, so it doesn't require creating an object to invoke the main() method.
So, it saves memory.
void is the return type of the method. It means it doesn't return any value.
main represents the starting point of the program.
String[] args or String args[] is used for command line arguments. We will discuss it in the coming section.
System.out.println() is used to print statements. Here, System is a class, out is an object of the PrintStream class, println() is a method of the PrintStream class.
We will discuss the internal working of system.out.println() statement in the coming section.
Java Applications
There are mainly 4 types of applications that can be created using Java programming:
1) Standalone Application
Standalone applications are also known as desktop applications or window-based applications. These are traditional software that we need to install on every machine. Examples of standalone application are Media player, antivirus, etc. AWT and Swing are used in Java for creating standalone applications.
2) Web Application
An application that runs on the server side and creates a dynamic page is called a web application. Currently, Servlet, JSP, Struts, Spring, Hibernate, JSF, etc. technologies are used for creating web applications in Java.
3) Enterprise Application
An application that is distributed in nature, such as banking application, etc. is called an enterprise application. It has advantages like high-level security, load balancing, and clustering. In Java, EJB is used for creating enterprise applications.
4) Mobile Application
An application that is created for mobile devices is called a mobile application. Currently, Android and Java ME are used for creating mobile applications.
Java Platforms: There are 4 platforms or editions of Java:
1) Java SE (Java Standard Edition)
It is a Java programming platform. It includes Java programming APIs such as java.lang, java.io, java.net, java.util, java.sql, java. math etc. It includes core
topics like OOPs, String, Regex, Exception, Inner classes, Multithreading, I/O Stream, Networking, AWT, Swing, Reflection, Collection, etc.
2) Java EE (Java Enterprise Edition)
It is an enterprise platform that is mainly used to develop web and enterprise applications. It is built on top of the Java SE platform. It includes topics like Servlet, JSP, Web Services, EJB, JPA, etc.
3) Java ME (Java Micro Edition)
It is a micro platform that is dedicated to mobile applications.
4) JavaFX
It is used to develop rich internet applications. It uses a lightweight user interface API.
Post updated on: Jan 28, 2023 1:27:44 PM
Role of
History in tourism Industry
Generally history is offered as a product in tourism. History
figures predominantly in promotional literature. Many destinations have always
been promoted through their histrocity like Jaipur , Pink city , City of
palaces , Fatehpur Sikri etc.
Similarly in travel writing
history is a popular theme to write upon and it can be history of many things- destination, fort, palace, art and crafts ,people , airline etc. But history
plays an important role in the area of Indian tourism as India is primarily a
cultural destination in the International tourism. Not only in the
International tourism but in domestic tourism also history and its by products
remain prime attractions.
People often plan their trend to have a feel of their
cultural heritage along with several other interests. So tourism is the most
important area today where history seems
to become operative as an attraction , the pull factor or product for the
consumption of tourists.
As a tourism product ,it figures in the
-
Promotional
literature
-
Travel
and tourism writing
-
Descriptions
and interpretations provided by guides and escorts.
Offering
historical destinations and museums as travel packages has been an old trade
with tourism industry. With the growth of special interest tourism the
relevance of history has further increased.In many cases fairs and festivals
have also emerged as strong tourist attractions because they provide a good
example of continuity and change.
The age old rituals ,traditions and customs
are located in modern ambience in these fairs and festivals. History also
figures in the shopping and entertainment because many tourists want to know
the history of designs and styles etc. of jewellery and craft items. Thus
history is very important for Indian tourism .
Post updated on: Jan 9, 2023 9:23:16 AM
Qualities
of a travel writer
1.
The writer should not be prejudiced. One
should have an open mind while approaching the
subject. Even if there are any
preconceived ideas that have to be tested on the basis of ground realities.
2.
A certain amount of preparatory effort is a
must for any write up like reading about the place or theme to be covered.
Familiarizing oneself with history, geography , culture is another exercise in
this regard.
3.
Constant
updating of knowledge and information is a must for a writer. Providing outdated
information in a write up would not help anyone. At times the writer has to be
a researcher also.
4.
Facts
have to be vetted.
5.
Not
everyone can write on everything. Hence one should attempt to discover ones own
skills and interests keeping in view the limitations and abilities. The
personal style of writing also has to be taken account of.
6.
Collated
information gathered from various sources forms the basis of many write ups. It
is always better for the writer to record personal experiences and assessment.
7.
Since
visuals supplement the richness of a write up meaningful photographs and
illustrations should be there. It is good for a writer to develop the skill of
photography or else utilize the services of a professional.
Post updated on: Jan 8, 2023 1:21:55 AM
Various services
required by Tourists
1.
Eating joints and bars: -
Different types of eating joints cater to the tourists. These range from
restaurants and tea stalls to Dhabas and fast food counters. Local cuisine is
generally popular with the tourists
because they prefer to eat the local food of the particular destination. Thus
one should not just initiate western foods or joints but also give due
importance to local goods and customs related to it.
2.
Entertainment and recreation: - Entertainment is an essential
component in tourism. On an average foreign tourists in India spend about 10%
of their total expenditure on entertainment. The tourists are provided
entertainment through various means specially at night or in the evening. This
may include dance, theater , movies, theme dinner and musical evening etc.
Similarly many hotels organize musical nights or dance performances during the
tourist season. Another recent development is the organizing of short duration
entertainment festivals by some State tourism departments like the Qutub
festival in Delhi or Taj festival at Agra.
3.
Communication: - As tourists are away from their homes and work environment so they may want to
communicate back home with family members or friends etc. Thus they need
communication services like post office and public call booths . In recent
years the number of STD / ISD booths have gone up to take care of such demands.
4.
Book shops and libraries: - Tourists want to read books during the long journey or just
to relax themselves. That is the reason we see various book stalls at airports
, railway platforms and bus stands.
5.
Photography: -
One of the most popular services at destination is that of photographers.
Tourists not only like to be photographed in the surroundings but also in the
costume and attire of the region they visit. In almost all the hill stations we
come across photographers with local dresses and tourists generally change into
that attire and for a snap.
Post updated on: Jan 8, 2023 1:21:20 AM
Functions
of Travel Agency
The
functions of a modern travel agency have widened much after the introduction of
air travel. The most important functions of a travel agency are described
below.
1.
Travel Information: - A retail travel agency provides necessary travel information to the
general public. The intending tourists come to the office of the travel agent
and seek information regarding their proposed visit. The travel agent should be
a very knowledgeable man and should supply up to date and concrete information
relating to travel.
2.
Preparation of itineraries: - A tourist journey involves preparation of different types
of itineraries. There are different means of transport with their respective
advantages and disadvantages. A travel agent advises the potential tourist to
choose the most convenient course.
3.
Planning and costing tours: - The contracts and
arrangements having been entered into ,there comes the task of planning and
costing tours,both for inclusive programs and to meet individual
requirements. This job is intensely interesting and at the same time
challenging.
4.
Ticketing: -
Selling tickets to tourists for different modes of transport like air, rail and
sea is a very important function of a travel agent. Ticketing is not an easy
job as the range of international air fares is very complex.
5.
Provision of foreign currencies: - Provision of foreign currency to an intending foreign tourist
is an important function of travel agent.
6.
Liaison with providers of service: - A travel agent should maintain constant contact with the
providers of various services like the transport companies, hotel managers and
providers of surface transport like motor cars from airport to hotel and for
sightseeing etc.
Post updated on: Jan 8, 2023 1:20:13 AM
Types of
tourism
1.
Business tourism: - It is touring for conducting business transactions ,attending business
meeting s, workshops or conferences . The objective of business tourism is
mainly professional.
2.
Cultural tourism: - This type of tourism has an objective of understanding the local
history of the place,foods, local productions and local culture.
3.
Recreational tourism: - It includes traveling to escape from routine life. This is often done
for enjoyment ,amusement or pleasure.
e.g
Camping or beach visit.
4. Sports tourism: - It is
tourism for attending some sports event
such as World cup, cricket match,
FIFA or Olympics.
5
Religious tourism: - It involves traveling to place of religious significance such as Vaishno Devi in
Jammu Kashmir and Golden temple at Amritsar ,Mecca in Saudi Arabia.
6. Health or Medical tourism: - It involves traveling to improve
one?s health.It is with the objective of
visiting weight loss camps , nephropathy centers and health resorts.
7. Adventure tourism: - It
involves tourism for adventurous activities such as rock climbing, bungee
jumping ,sky diving, hiking, horse riding ,surfing,rafting.
8.
Educational tourism: - Educational tourism is a type of tourism in
which the main focus of the tour or leisure activity includes visiting another
country to learn about the culture such as in Student exchange programs and
study tours or to work and apply skills learned inside the classroom in a
different environment.
9. Rural tourism- It is a form
of tourism that showcases the rural life, art,culture and heritage at rural locations thereby
benefiting the local community ,economically and socially as well as enabling
interaction between the tourists and the locals for a more enriching tourism
experience.
10.
Agrotourism - Agrotourism
is farm based tourism . It refers to the act of visiting a working farm of any
agricultural , horticultural or agrobusiness operation for purpose of enjoyment
, education or active improvement in the activities of the farm or operation.
Post updated on: Jan 8, 2023 1:18:20 AM
Well, often, when I ask my students, " What is Success to
you? " . The usual answer is ," Mam, Lot of money, good life, good
lifestyle, Owning a Mercedes Benz, Big House and the list is on and
on....Really? How do you define good life? And to my surprise, they
don't even know the meaning of happiness!! the difference between
pleasure and happiness. May I ask you," Do you know? Is it so difficult
to be happy? Actually, it's very simple. We are so lost in our own
world's, the so called race of life. when actually, life has never been a
race. Like the different fingers in our hands, each one of us are
unique in ourselves and have their own journey!! " A self satisfied
life is much better than a successful life because success is measured
by others , but satisfaction is measured by your soul. A successful
person may or may not be happy but a happy person will always be
successful and satisfied. Life has a different exam for everyone which
cannot be copied .To me, Success is ," To aim to become a better version
of myself each day, on the path of my journey, following my passions,
soul mission and convictions!! "
So, again here, at an event organized by an International
NGO, Where I had given a session on Interview skills to about 150 girls
Alumini students from different schools and colleges, one student
defined success as Lot of money!! So, to say,, All of us are Energies
and even Money is also an Energy , which is meant to flow.
Like always, it is a beautiful feeling, when some of the
students came to me after the session and shared that, Mam, I was so
nervous before my Mock Interview with you but now I feel much better and
so confident, I have learnt a lot from you today. Thank you so much,
Mam!!" Now, this feeling of peace and happiness where I am able to make a
positive change in someone's life, That's real happiness, and the
purpose of my life. The mission of my life. What you leave behind is how
many faces smile when they hear your name and remember you , Your words
, your deeds is what matters ultimately. Be a good human being and Be
happy always!!
Keep reading for more!! Do share your thoughts as well, I would love to read.
Stay safe, Stay blessed and stay happy always!!
Shalini
Post updated on: Nov 28, 2022 7:27:07 PM
Some of my Experiences and Learnings!!
Well,
I just love this festival because so much of lights around, killing the
darkness, light reaches everywhere, as if Universe is showering it's
blessings on all of us. After 2 long years of waiting, this Diwali had a
very mixed feeling, as some of my friends had lost their closed ones
unfortunately, so they could not celebrate and some others celebrated
very well with a lot of happiness and smile on their face. As if life
was slowly finally coming back to normal like old times. It was so good
and beautiful to see light everywhere around in a series like always. As
there is light after the tunnel and the tunnel was finally over .
An
old friend of mine visited my place, after long 5 years and we
cherished childhood memories and created some more beautiful ones. Good
to feel that some things don't change and should not change. An old
shopkeeper near my place, I used to visit often to buy some stuff, he
was still there selling similar stuff. And he didn't forget me and
recognized me, asking if I am fine and all well.
Same
time, all of us light Diyas in the evening, so we see series of light
everywhere killing the darkness. But what about the darkness in our
hearts? Have we ever thought about it? What do we learn from Diwali?
Here are some of my learnings-
* Liberate ourselves from all the negative memories of the past.
* Forgiving everybody who has hurt us in any form and fill our hearts with love and peace.
* Kindness- A small act of polite words, kindness, humanity can go a long way. It might just change some one's life
* Happiness- Happiness within ourselves and spreading it too.
* Unity in diversity.
*
Liberating ourselves from all the negative feelings in our hearts like
Ego, Jealousy and fill our hearts with lots of positivity, hope and
faith.
Let's ignite that light within us and keep it alive always!!
Hope
all of you had a great Diwali full of beautiful memories like me. Do
share your experiences and learnings with me, I would love to read.
Keep reading for more!!
Stay safe, stay blessed and stay happy always!!
Post updated on: Nov 4, 2022 9:55:02 PM
There are certain assumptions surrounding makeup being tested on animals. Most of us think it?s nothing major and doesn?t really believe that it could amount to cruelty. So if you?re thinking that make up testing on animals is simply a monkey get its nails done or squirrels enjoying a sauna, you must know that the reality is actually quite grim and dark!
Animals that are deployed for testing are kept in complete isolation. They are forced to live a bleak life just for the sake of these tests which further add to their suffering. They are forcefully fed with the unrealistic proportions of products only for the purpose of observation by the scientists who are looking for the signs and symptoms of birth defects, cancers, and some other health issues. Their eyes are dilated with drugs and their skin is shaved and rubbed with the product to see whether they face any irritation or itching. To top it all, many times the poor animals are forced to take lethal dosages of chemicals to see what will kill them! This inhuman practice is prevalent across the makeup industry and many top brands are involved too.
The cosmetic industry is largely unregulated and thrives on the promise of making us look more. But the fact remains that in the absence of any concrete regulation and laws against animal testing, this is dependent almost entirely on the discretion of makeup companies who don?t really care about the cruelty factor. The animal testing methodology is absolutely cruel and archaic and simply not necessary when it comes to producing quality makeup products.
With the changing times there have been some positive drift against animal testing too. However, this is just the beginning as we need to go a long mile from here. Many countries like the U.S, UK, Australia, India, New Zealand and many more have come forward to stop this animal cruelty. There are many upcoming brands who are organic, pure, and made without performing any tests on animals whatsoever.
One such brand is MS Glamour that uses natural and organic ingredients that pose no threat to the planet or living beings. It aims to empowering and educating the consumers so that they can adapt to informed choices. We always believe in making people aware about what goes behind the scenes in make-up industry. We even make them clear on why are we always aiming at producing cruelty free make-up.
Now let?s discuss about the good news that has given some relief in the case of animal cruelty. Countries like US, India, Australia, Norway, New Zealand, Israel, Switzerland, U.K and Turkey and some other countries are also favouring a new law that talks of banning the testing conducted on innocent animals in Cosmetics industry.
This is a good beginning, but we still have a lot to cover in terms of collective thinking and empathy that we hold towards innocent animals. In China importers are still forced to test their cosmetic products on animals if they really want their supplies to stand in the Chinese market.
There are many organizations working for animal welfare that have statistics and records of animal cruelty caused by the cosmetic industry. Organizations like Mintel and PETA have estimated that 300,000 animals are used in cosmetics tests each year in China alone, with the Humane Society International estimating the death of 50,000 to 120,000 rabbits yearly over the past decade owing to cosmetic product testing.
While the above data is distressing but we do have some good news! In the month of July this year, China?s State Council announced that beginning January 1st, 2021, imported ?ordinary? cosmetics, such as shampoo, perfume, and mascara, may no longer require eye and skin irritation animal tests. A significant win for the animals and animal right activists, this regulation will surely pave the way for more concrete laws and lead to more concrete and positive changes in the right direction.
Make-up is a joy for the applicator, let?s make it free from cruelty too! Enjoy cruelty free make-up by MS Glamour!
Post updated on: Oct 24, 2022 10:10:58 PM
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