What is Keyword in Java?

In Java, a keyword is a reserved word that conveys a specific meaning to the Java compiler.

Keywords are special words that have a predefined meaning to the Java compiler. They are reserved words and cannot be used as an identifier, function names, class names, etc in a programming language. However, if try to use them as an identifier, variable name, etc then we will be getting a compile-time error.

Java contains 50 such keywords that are reserved for specific purposes in the Java language. Some of the keywords are int, break, implements, float, etc. Since they are reserved words that convey a special meaning to the Java compiler, therefore, they are highlighted with different colors in any IDE or editor to differentiate them from the other words.

In this article, we will be discussing all the keywords one by one that is predefined in Java.

List of all Java Keywords

For example: boolean b = true

 For example: 
     int i=0;
     while(i<10){
       if(i==4)
           break;
       i++;
     }

For example: 
     int i=1;
     switch(i){
       case 1:
         System.out.println(yes)    
         break;
     }

 For example: char ch = 'a';

class A{
   //statements
}

For example:
int i=0;
while(i<10){
  if(i==4){ 
     i++;
     continue;
  }
   System.out.println(i);
   i++; 
}

For example: 
     int i=1;
     switch(i){
       case 1:
         System.out.println(yes)    
         break; 
       default:
         System.out.println(-1);
     }

For example: 
     int i=1;
     do{
         System.out.println(yes);    
         i++; 
     }while(i<10);

For example: double d = 4.6786;

For example: 
if(1==2){
 System.out.println(true); 
} 
else{
 System.out.println(false);
}

For example: class A extends B.

For example: float f = 4.5f; 

 For example: for(int i=0;i<100;i++){ 
                //Statements..
              }

For example: 
if(1==2){
  System.out.println(true); 
} 

For example: import java.util.Scanner;

For example: int a = 5;

For example: long l = 400389l;

For example: int cal(int i){
                return i+1;
             }

 For example:
 void print(){
    System.out.println("Hello");
 }

For example:
int i=0;
while(i<10){
    System.out.println(i);
    i++;
}

What If We Use the Keywords as the Variable Name?

If we use the keywords as variable names in Java, they would give us a compile-time error as it is against the rules for naming a variable.

The rules for the naming convention of variables clearly mention that a variable name should not be a keyword. However, keywords are also reserved words for specific purposes and are not supposed to use for any other purpose in Java.

Let us see it with an example.

Output:

Learn More

You can refer to the following articles for more information on different keywords in Java.

• New Keyword in Java
• Super Keyword in Java
• Final Keyword in Java
• Transient Keyword in Java

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