Java Exception throw statement

Introduction

To throw an exception explicitly, using the throw statement.

The general form of throw is shown here: 

throw ThrowableInstance;

Here, ThrowableInstance must be an object of type Throwable or a subclass of Throwable.

To get a Throwable object: using a parameter in a catch clause or creating one with the new operator.

The flow of execution stops after the throw statement and any subsequent statements are not executed. 

public class Main {
  public static void main(String[] args) {
    try {/*from ww  w .j av  a  2 s .  c  o  m*/
      throw new Exception("test");
    } catch (Exception e) {
      System.out.println(e);
    }
  }
}

// Demonstrate throw.  
public class Main {  
  static void myMethod() {  
    try {  /*from w w  w.j a va  2 s .co  m*/
      throw new NullPointerException("demo");  
    } catch(NullPointerException e) {  
      System.out.println("Caught inside myMethod.");  
      throw e; // rethrow the exception  
    }  
  }  
  
  public static void main(String args[]) {  
    try {  
      myMethod();  
    } catch(NullPointerException e) {  
      System.out.println("Recaught: " + e);  
    }  
  }  
}

To create one of Java's standard exception objects. 

throw new NullPointerException("demo");



PreviousNext

Related