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Java try-catch block

Java try block

Try blocks are used in Java to contain code that might raise an exception. It has to be applied to the method.

When encountering an exception within a try block, the subsequent statements will not be executed. Hence, it is recommended to avoid placing non-exceptional code within the try block.
In the Java programming language, it is essential to have either a catch block or a finally block following every try block. This ensures proper handling of exceptions and execution of necessary cleanup code.

Table Of Content

Java try block
Java catch block
Problem without exception handling
Example of Exception Handling
Java Nested try block

Syntax of Java try block

try{    
 //code that could raise an exception
}

Java catch block

By stating the type of the exception within the parameter, the Java catch block is used to handle the exception. When dealing with Java Exception Handling, it is essential to declare the parent class exception (Exception) or the specific exception type generated as the declared exception. Declaring the generated type of exception is, however, the best course of action.
Only after the try block should the catch block be used. With a single try block, you can combine multiple catch blocks.

Syntax of Java catch block

catch{
   // statement(s) that handle an exception
}

Problem without exception handling

public class Main {	
    public static void main(String args[]){  		 
        int num=20/0; //it will arise  exception  
        System.out.println("Hello World");  
   } 
}

Output:

java.lang.ArithmeticException: / by zero
This Code is unaffected to exception handling

Exception is arise when we try to divide by zero so rest of code(Hello World) not printed to handle this situation we use exception handling

Example of Exception Handling

package DockerTpoint;
public class Main {	
    public static void main(String args[]){  		 
	  try{  
	      int Num=10/0;  //code inside try block may raise exception
	      System.out.println(Num);
	   }
	  catch(ArithmeticException e){
		  e.printStackTrace();
	  }   // code below catch block will execute normally
      System.out.println("This Code is unaffected to exception handling");  
   } 
}

Output:

 java.lang.ArithmeticException: / by zero
	at HELLO/DockerTpoint.Main.main(Main.java:5)
This Code is unaffected to exception handling

Exception is arise and handled by catch block and rest of code(This Code is unaffected to exception handling) get printed this is reason why we use exception handling

Example of Exception Handling and rest of code

package DockerTpoint;
public class Main {	
    public static void main(String args[]){  		 
	  try{  
	      int Num=10/0;  //code inside try block may raise exception
	      System.out.println(Num);
	      System.out.println("Code Inside Try Block");
	   }
	  catch(ArithmeticException e){
		  e.printStackTrace();
	  }   // code below catch block will execute normally
      System.out.println("This Code after catch block");  
   } 
}

Output:

 java.lang.ArithmeticException: / by zero
	at HELLO/DockerTpoint.Main.main(Main.java:6)
This Code after catch block

Exception is arise and handled by catch block but code inside try block is not get printed but rest of code(This Code after catch block) get printed

Example of Exception Handling with Custom Message

package DockerTpoint;
public class Main {	
    public static void main(String args[]){  		 
	  try{  
	      int Num=10/0;  //code inside try block may raise exception
	      System.out.println(Num);
	      System.out.println("Code Inside Try Block");
	   }
	  catch(ArithmeticException e){
		  System.out.println("unable to divide by zero");  
	  }
      System.out.println("This Code after catch block");  
   } 
}

Output:

unable to divide by zero
This Code after catch block

Exception is arise and handled by catch block but catch block print custom message

Example of Exception Handling when resolvd the exception in catch block

package DockerTpoint;
public class Main {	
    public static void main(String args[]){ 
	   int Num1=10;  
	   int Num2=0;
	  try{  
	      System.out.println(Num1/Num1/Num2);
	      System.out.println("Code Inside Try Block");
	   }
	  catch(ArithmeticException e){
		  Num2=5;
		  System.out.println(Num1/Num2);
	  }
      System.out.println("This Code after catch block");  
   } 
}

Output:

 2
This Code after catch block

Exception is arise and handled but resolvd the exception in catch block

Java Nested try block

Java allows the use of try blocks inside of other try blocks. The term "nested try block" describes it. The context of the exception is pushed onto the stack with each statement we enter in a try block.

For example in the case, the outer try block can handle the ArrayIndexOutOfBoundsException while the inner try block can handle the ArithemeticException.

There are times when a block may contain a portion that causes one error while the entire block itself causes a different error. Such circumstances necessitate nesting of exception handlers.

Example of Nested try block

public class Main {	
    public static void main(String args[]){    	 
	  try{    
		    try{   //inner try block 1 
		     System.out.println("inner try block");    
		     int Num1 =10/0;    
		    }  
		    catch(ArithmeticException e){  //inner catch block 1 
		      System.out.println(e);  
		    }
		    
		    try{     //inner try block 2
			     int arr[]=new int[10]; 
			     arr[15]=15;    
		     }   
		    catch(ArrayIndexOutOfBoundsException e){  //inner catch block 2 
		       System.out.println(e);  
		    }        
	  }   	  
	  catch(Exception e){  
	    e.printStackTrace(); 
	  }        
	  System.out.println("This Code after outer catch block");  
   } 
}

Output:

inner try block
java.lang.ArithmeticException: / by zero
java.lang.ArrayIndexOutOfBoundsException: Index 15 out of bounds for length 10
This Code after outer catch block

Java Multiply Catch Block Next »

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Java try-catch block

Java try block

Syntax of Java try block

Java catch block

Syntax of Java catch block

Problem without exception handling

Example of Exception Handling

Example of Exception Handling and rest of code

Example of Exception Handling with Custom Message

Example of Exception Handling when resolvd the exception in catch block

Java Nested try block

Example of Nested try block

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