Convert List to Map using Google Guava in Java

Here is a simple example that shows conversion of a List (java.util.List) to Map (java.util.Map) using Google’s Guava API.

Other Google Guava examples:
Iterables Find Example
Iterables Any Example
Better null checks using Optional Example
Convert Map to String

package com.idodevjobs;


import java.util.List;
import java.util.Map;

public class GoogleGuavaListToMap {

    private String input;

    public GoogleGuavaListToMap(String input) {
        this.input = input;

    public static void main(String[] args) {

        List yourList = Lists.newArrayList(new GoogleGuavaListToMap("input1"), new GoogleGuavaListToMap("input2"));

        Map newMap = Maps.uniqueIndex(yourList, new Function<GoogleGuavaListToMap, String>() {
            public String apply(GoogleGuavaListToMap googleGuavaListToMap) {
                return googleGuavaListToMap.getInput(); // or something else


    public String getInput() {
        return input;

    public void setInput(String input) {
        this.input = input;

    public String toString() {
        return "GoogleGuavaExample{" +
                "input='" + input + '\'' +

In this example, we are iterating through the List for unique objects and creating key-value pairs using the contents of the List to eventually create a map.

Leave comments should you have any questions.

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4 Responses to Convert List to Map using Google Guava in Java

  1. Pingback: Google Guava Iterables Find Example | iDoDevJobs

  2. Pingback: Google Guava Iterables Any Example | iDoDevJobs

  3. Pingback: Google Guava Optional Example | iDoDevJobs

  4. Pingback: Convert Map to String using Google Guava in Java | iDoDevJobs

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