Java - convert String to Enum object

Short solution:

public class Example1 {

    enum ColorEnum {
        RED,
        GREEN,
        BLUE
    }

    public static void main(String[] args) {

        String color = "BLUE";

        // we use valueOf on our enum class
        ColorEnum colorEnum = ColorEnum.valueOf(color);

        System.out.println(colorEnum); // BLUE
    }
}

In java we can simply convert String to enum by using .valueOf() method on our Enum class.

Example:

MyEnumClass.valueOf("MY_ENUM_CONSTANT")

Note:

We need to use the name of enum value exactly like it is defined.

• letter size must be the same
• if uppercase letters then we need to use uppercase
• if lowercase letters then we need to use lowercase
• no spaces
• no white spaces

If we don't have exact match then we get exception:

java.lang.IllegalArgumentException: No enum constant ...

1. Documentation - Enum valueOf() method

2. Using Enum value() and String.toUpperCase()

public class Example2 {

    enum ColorEnum {
        RED,
        GREEN,
        BLUE
    }

    public static void main(String[] args) {

        String color = "blue";
        color = color.toUpperCase();

        ColorEnum colorEnum = ColorEnum.valueOf(color);
        System.out.println(colorEnum); // BLUE
    }
}

Output:

BLUE

3. Case with No enum constant

public class Example3 {

    enum ColorEnum {
        RED,
        GREEN,
        BLUE
    }

    public static void main(String[] args) {

        String color = "WHITE";
        ColorEnum colorEnum = ColorEnum.valueOf(color);

        System.out.println(colorEnum);
    }
}

Output:

Exception in thread "main" java.lang.IllegalArgumentException: 
No enum constant com.dirask.Example3.ColorEnum.WHITE
	at java.lang.Enum.valueOf(Enum.java:238)

Common mistakes

1. Java enum valueOf uppercase or lowercase - does it matter when I use enum value of?

Merged questions

1. Java - get enum value from String value
2. Java - how to convert String to enum object? 
3. How to cast String to enum value in java?