Multiple catch blocks in Java - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of multiple catch blocks in Java?

Multiple catch blocks allow a program to handle different types of exceptions separately, providing specific responses for each exception type.

beginner

How does Java decide which catch block to execute when an exception occurs?

Java checks the exception type thrown and matches it with the first compatible catch block in order. It executes the first matching catch block and skips the rest.

beginner

Can you have multiple catch blocks for a single try block in Java?

Yes, you can have multiple catch blocks after a single try block to handle different exception types separately.

intermediate

What happens if a more general exception catch block is placed before a more specific one?

The compiler will give an error because the more general catch block will catch all exceptions of that type and its subclasses, making the specific catch block unreachable.

beginner

Write a simple Java try-catch example with multiple catch blocks for ArithmeticException and NullPointerException.

try { int result = 10 / 0; String text = null; System.out.println(text.length()); } catch (ArithmeticException e) { System.out.println("Cannot divide by zero."); } catch (NullPointerException e) { System.out.println("Null value encountered."); }

What will happen if an exception is thrown that does not match any catch block?

A The program will terminate with an uncaught exception error.

B The first catch block will handle it anyway.

C The program will ignore the exception and continue.

D Java will automatically create a catch block.

If no catch block matches the thrown exception, the program terminates with an uncaught exception error.

Which catch block will execute if both ArithmeticException and Exception catch blocks are present and an ArithmeticException is thrown?

A The catch block for Exception.

B The catch block for ArithmeticException.

C Both catch blocks execute.

D None will execute.

Java executes the first matching catch block. Since ArithmeticException is more specific, its catch block runs.

Is it valid to have multiple catch blocks for the same exception type?

A No, it causes a compile-time error.

B No, Java merges them automatically.

C Yes, but only if they are in different try blocks.

D Yes, to handle the same exception differently.

Having multiple catch blocks for the same exception type in the same try block causes a compile-time error.

What is the correct order of catch blocks?

A Only one catch block is allowed.

B From most general to most specific exception.

C Order does not matter.

D From most specific to most general exception.

Catch blocks must be ordered from most specific to most general to avoid unreachable code errors.

Can a try block have no catch blocks?

A Yes, but only in Java 17+.

B No, catch blocks are mandatory.

C Yes, if it has a finally block.

D No, try blocks must always have catch blocks.

A try block can have no catch blocks if it has a finally block to handle cleanup.

Explain how multiple catch blocks work in Java and why their order matters.

Think about how Java matches exceptions to catch blocks.

Write a Java try-catch example with at least two catch blocks for different exceptions and explain what each block does.

Use ArithmeticException and NullPointerException for clarity.