Java throws vs throw: Key Differences

In Java, throws and throw are two different keywords used to handle exceptions.

1. The ‘throws’ keyword is used in methods to indicate that an exception may be thrown, but the method itself does not handle the exception, instead passing it on to the caller to handle. Using the ‘throws’ keyword in a method declaration informs the caller of possible exceptions that may occur, requiring the caller to either catch or continue to pass on the exception.

public void doSomething() throws IOException {
    // 可能会抛出IOException的代码逻辑
}

1. The “throw” keyword is used to manually throw an exception object, which can be either a system-provided exception class object or a custom exception class object. When the program reaches a “throw” statement, it immediately throws the exception and does not continue to execute any code after the “throw” statement.

if (condition) {
    throw new IOException("An error occurred");
}

In summary, “throws” is mainly used in method declarations to indicate the types of exceptions that a method may throw, while “throw” is used in specific code blocks to manually throw exception objects. “throws” is used for declaration, while “throw” is used for actually throwing exceptions.