@Override annotation was introduced in Java 1.5.

@Override annotation indicates that the element is meant to override an element declared in super class.

It is not required to use this annotation while overriding a method, but using @Override annotation helps in preventing errors.

If you do not override a method marked with @Override correctly, the compiler will generate compilation error.

public class Employee{
	private String name;
	
	/*This method will result in compilation error as
	 * it is incorrectly trying to override equals method.
	*/
	@Override
	public boolean equals(Employee employee){
		return name.equals(employee.name);
	}
}

In this example, programmer is trying to override equals() method but instead has resulted in overloaded method. If @Override annotation is not used, compiler will not give any error as well as no exception will not be thrown at run time.

With @Override annotation, compiler will check if this method overrides a super class or interface method correctly or not. If it does not override correctly then it will throw compilation error ‘The method equals(Employee) of type Employee must override or implement a supertype method’ in this case.

So, using @Override annotation saves time by avoiding errors related to overriding.

A programmer should always consider using this @Override annotation when dealing with many sub classes and overriding code. This will help in saving errors and debug time.

In short @Override annotation:

• Helps is saving from hard to find errors and debug time by raising compilation errors when method is not overridden correctly.
• Helps in improving readability of the code.