throw error java

In Java, the throw keyword is used to throw an exception, which indicates that an error or exceptional condition has occurred during the execution of a program.

Here's an example of how you can use the throw keyword to throw an exception in Java:

if (value < 0) {
  throw new IllegalArgumentException("Value must be non-negative");
}

In this example, the throw keyword is used to throw an IllegalArgumentException if the value is negative. The exception is created using the new operator and is passed a message describing the error.

It's important to note that the throw keyword must be followed by an instance of a class that extends the Throwable class (such as Exception or Error). You cannot throw a primitive type or a string using the throw keyword.

Exceptions can be caught and handled using a try-catch block. The try block contains the code that may throw an exception, and the catch block contains the code that handles the exception.

Here's an example of how you can use a try-catch block to handle an exception thrown with the throw keyword:

try {
  if (value < 0) {
    throw new IllegalArgumentException("Value must be non-negative");
  }
}
catch (Exception e) {
    e.printStackTrace();
}