Java Nested try Blocks

Last Updated: 06 March, 2023

Java allows to write one try block inside another try block, which is known as a "nested try block."

A nested try block is used when a part of a block may cause one error and the entire block itself may cause another error. In such cases, exception handlers have to be nested.

Syntax of nested try block

    ....
  // Outer try block
  try {
    statement 1;
    statement 2;
    // try-catch block inside another try block
    try {
        statement 3;
        statement 4;
        // try-catch block inside nested try block
        try {
          statement 5;
          statement 6;
        }
        catch(Exception e2) {
          // Exception Message
        }
    }
    catch(Exception e1) {
        // Exception Message
    }
  }
  // Catch of outer try block
  catch(Exception e3) {
      // Exception Message
  }
  ....

Example 1: Java nested try block

  public class NestedTryExample1 {
    public static void main(String[] args) {
      String num[] = { "10", "20", "30", "abc", "50", "60", "70" };
  
      // outer try block
      try {
        for (String str : num) {
          // inner try block
          try {
            System.out.println(Integer.parseInt(str));
          } catch (NumberFormatException e) {
            System.out.println("Exception occured in the inner try block...");
          }
        }
      } catch (Exception e) {
        System.out.println("Exception occured in the outer try block...");
      }
  
      System.out.println("Code after outer try block...");
    }
  }

Output

10
20
30
Exception occured in the inner try block...
50
60
70
Code after outer try block...

Example 2: Java nested try block

  public class NestedTryExample2 {
    public static void main(String[] args) {
      int num1 = 10;
      int num2 = 0;
  
      // outer try block
      try {
        System.out.println("Dividing both numbers:");
        System.out.println("Output: " + num1 / num2);
        // inner try block
        try {
          System.out.println("Inner try block");
        } catch (NumberFormatException e) {
          System.out.println("Exception occured in the inner try block...");
        }
        System.out.println("Code after inner try block...");
      } catch (ArithmeticException e) {
        System.out.println("Exception occured in the outer try block...");
      }
  
      System.out.println("Code after outer try block...");
    }
  }

Output

Dividing both numbers:
Exception occured in the outer try block...
Code after outer try block...

Example 3: Java nested try block

  public class NestedTryExample3 {
    public static void main(String[] args) {
      String[] fruits = { "Apple", "Mongo", null, "Grapes" };
      
      // outer try block
      try {
        System.out.println("Outer try block...");
  
        for (String fruit : fruits) {
          // inner try block
          try {
            System.out.println(fruit.toUpperCase());
          } catch (NumberFormatException e) {
            System.out.println("Exception occured in the inner try block...");
          }
        }
      } catch (Exception e) {
        System.out.println("Exception occured in the outer try block...");
      }
      
      System.out.println("After Outer try block...");
    }
  }

Output

Outer try block...
APPLE
MONGO
Exception occured in the outer try block...
After Outer try block...

Java Nested try Blocks

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