How to return an array of enums, get this error

public enum colors{
Green,
YELLOW,
RED,
ERROR;
   public static colors[] values(){
/*
 Returns an array containing the constants of this enum type, in the order they are declared.
*/
   colors[] c = {GREEN,YELLOW,RED,ERROR};
   return c;
   }
}

get the error: values() is already defined in colors

This method is implicitly defined by the compiler, so if you will try to declare this method again into your enum, you will get compile error like "The enum <class-name>.colors already defines the method values() implicitly"

You can check the documentation here, https://docs.oracle.com/javase/specs/jls/se7/html/jls-8.html#jls-8.9.2

Note this line in the above documentation,

"It follows that enum type declarations cannot contain fields that conflict with the enum constants, and cannot contain methods that conflict with the automatically generated methods (values() and valueOf(String)) or methods that override the final methods in Enum (equals(Object), hashCode(), clone(), compareTo(Object), name(), ordinal(), and getDeclaringClass())."

Here, E is the name of an enum type, then that type has the following implicitly declared static methods.

/**
* Returns an array containing the constants of this enum 
* type, in the order they're declared.  This method may be
* used to iterate over the constants as follows:
*
*    for(E c : E.values())
*        System.out.println(c);
*
* @return an array containing the constants of this enum 
* type, in the order they're declared
*/
public static E[] values();

Therefore you do not need to declare it again, instead you can get array by simply calling colors.values().

For an Example, refer the below simple code snippet:

public class Test {
   
	public static void main(String[] args) {
		colors[] values = colors.values();
		System.out.println(Arrays.toString(values));
	}
	
	public enum colors {
		Green,
		YELLOW,
		RED,
		ERROR;
	}	
}

OUTPUT:

[Green, YELLOW, RED, ERROR]

Enums in java will have a generated static method values(), and it cannot be overriden , as specified in the Java Spec.

Please check the documentation

The compiler automatically adds some special methods when it creates an enum. For example, they have a static values method that returns an array containing all of the values of the enum in the order they are declared. This method is commonly used in combination with the for-each construct to iterate over the values of an enum type. For example, this code from the Planet class example below iterates over all the planets in the solar system.