Immutable Map Builder 

Google Guava is a java library with lot of utilities and reusable components. This requires the library guava-10.0.jar to be in classpath. The following example shows using ImmutableMap.Builder class. It returns an immutable map implementation which doesn't allow null keys and values.

File Name  :   com/bethecoder/tutorials/guava/collection_tests/ImmutableMapBuilderTest.java  Author  :   Sudhakar KV Email  :   [email protected]

package com.bethecoder.tutorials.guava.collection_tests; import java.util.Map; import com.google.common.collect.ImmutableMap; public class ImmutableMapBuilderTest {   /**    * @param args    */   public static void main(String[] args) {     Map<String, Integer> immutableMap =          new ImmutableMap.Builder<String, Integer>()           .put("ONE", 1)           .put("TWO", 2)           .put("THREE", 3).build();     System.out.println(immutableMap);          immutableMap = ImmutableMap.<String, Integer>builder()             .put("ONE", 1)             .put("TWO", 2)             .put("THREE", 3).build();     System.out.println(immutableMap);   } }

{ONE=1, TWO=2, THREE=3}
{ONE=1, TWO=2, THREE=3}