Can enum implement an interface in Java?

Enum can implement an interface in Java (Enum can have abstract methods too).

 

Example

enum StringConverters implements Converter<String> {
		LOWER {

			@Override
			public String convert(String str) {
				return str.toLowerCase();
			}

		}
}

 

Find the below working application.

 

EnumImplementInterface.java

package com.sample.app;

public class EnumImplementInterface {

	interface Converter<T> {
		T convert(T data);
	}

	public static enum StringConverters implements Converter<String> {
		LOWER {

			@Override
			public String convert(String str) {
				return str.toLowerCase();
			}

		},
		UPPER {

			@Override
			public String convert(String str) {
				return str.toUpperCase();
			}

		},
		CAMELCASE {

			@Override
			public String convert(String str) {
				return toCamelCase(str);
			}

		};

		private static String toCamelCase(final String str) {
			if (str == null || str.isEmpty())
				return null;

			final StringBuilder builder = new StringBuilder();

			for (final String word : str.split(" ")) {
				if (!word.isEmpty()) {
					builder.append(Character.toUpperCase(word.charAt(0)));
					builder.append(word.substring(1).toLowerCase());
				}
				if (!(builder.length() == str.length()))
					builder.append(" ");
			}

			return builder.toString();
		}
	}

	public static void main(String[] args) {
		String str = "Hi Krishna, how are you";

		System.out.println(StringConverters.LOWER.convert(str));
		System.out.println(StringConverters.UPPER.convert(str));
		System.out.println(StringConverters.CAMELCASE.convert(str));
	}

}

Output

hi krishna, how are you
HI KRISHNA, HOW ARE YOU
Hi Krishna, How Are You

 

 

  

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