Java Try-Catch

Intermediate ~15 min read

The try statement allows you to define a block of code to be tested for errors while it is being executed.
The catch statement allows you to define the action to be taken if an error occurs in the try block.

Syntax

try {
  //  Block of code to try
}
catch(Exception e) {
  //  Block of code to handle errors
}

Example

If an error occurs, we can use try...catch to "catch" the error and execute some code to handle it instead of letting the program crash.

try {
  int[] myNumbers = {1, 2, 3};
  System.out.println(myNumbers[10]); // Error!
} catch (Exception e) {
  System.out.println("Something went wrong.");
}

Without the try-catch block, the program would stop immediately and show a scary error message to the user.

public class TryCatchExample {
    public static void main(String[] args) {

System.out.println("--- Start of Program ---");

try {
            // 1. Array Index Out of Bounds
            int[] myNumbers = { 1, 2, 3 };
            System.out.println(myNumbers[10]);

// This line will NOT be executed because error happened above
            System.out.println("This will not print");

} catch (Exception e) {
            // 2. Handling the error
            System.out.println("Something went wrong!");
            System.out.println("Error Details: " + e.getMessage());
        }

// 3. Program continues
        System.out.println("--- End of Program (Graceful Exit) ---");

// --- Another Example with Division ---

System.out.println("\n--- Division Example ---");
        try {
            int result = 10 / 0;
            System.out.println("Result: " + result);
        } catch (ArithmeticException e) {
            System.out.println("Math Error: You cannot divide by zero.");
        }
    }
}

Output

Click Run to execute your code

Debugging

Inside the catch block, you usually want to print details about the error so you can fix it. You can print the exception object e or call e.printStackTrace().

catch (Exception e) {
  System.out.println("Error: " + e.getMessage());
  e.printStackTrace();
}

Summary

Put code that might throw an error inside try { ... }.
Put code to handle the error inside catch(Exception e) { ... }.
This prevents your application from crashing unexpectedly.

Previous Exception Basics

Next Multiple Catch Blocks →

Syntax

Example

Debugging

Summary

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