Filter list in list Java 8

In this tutorial, we are going to show you how to filter a stream of objects in Java 8. We can filter the string values and as well as objects using the Java 8 Stream filter.

Java 8 Stream Filter :

The filter[] in Java 8 is a method which is coming from the Stream interface, which returns the Stream object consisting of the elements of this stream that matches the given Predicate[action].

Legacy way of filtering the list in Java :

List list = new ArrayList[]; list.add["Java"]; list.add["Spring"]; list.add["Hibernate"]; list.add["Java8 Filter"]; list.add["JQuery"]; list.add["Hibernate 4"]; list.add["AngularJs"]; list.add["Java8 Streams"]; for [String sub : list] { if [sub.contains["Java8"]] { System.out.println[sub]; } }

The similar way of filtering the list of strings using Java 8 Stream Filter.

List subjects = list.stream[] .filter[sub -> sub.contains["Hibernate"]] .collect[Collectors.toList[]]; subjects.forEach[System.out::println];

Stream Filter with Strings :

package com.onlinetutorialspoint.java8; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; public class Java8_Streams_filter { public static void main[String[] args] { List list = new ArrayList[]; list.add["Java"]; list.add["Spring"]; list.add["Hibernate"]; list.add["Java8 Filter"]; list.add["JQuery"]; list.add["Hibernate 4"]; list.add["AngularJs"]; list.add["Java8 Streams"]; java8_filter[list]; } public static void normal_filter[List list] { for [String sub : list] { if [sub.contains["Java8"]] { System.out.println[sub]; } } } public static void java8_filter[List list] { List subjects = list.stream[].filter[sub -> sub.contains["Hibernate"]].collect[Collectors.toList[]]; subjects.forEach[System.out::println]; } }

Recommended: How to use Java8 foreach
Output:

Hibernate Hibernate 4

Stream Filter with Objects :

We can filter the list of user-defined objects using the Stream filter in Java. Here I am going to create a Subject POJO class to filter the elements.

Student.java [POJO]

class Subject { private int subId; private String subName; public Subject[int subId, String subName] { super[]; this.subId = subId; this.subName = subName; } public int getSubId[] { return subId; } public String getSubName[] { return subName; } }

Stream Filter with Objects Example :

package com.onlinetutorialspoint.java8; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; public class Java8_Streams_filter { public static void main[String[] args] { List subjects = Arrays.asList[new Subject[1, "Java"], new Subject[2, "Spring"], new Subject[3, "Hiberate"]]; java8_filterObjects[subjects]; } public static void java8_filterObjects[List subjects] { Subject subject = subjects.stream[].filter[name -> "Java".equals[name.getSubName[]]].findAny[].orElse[null]; System.out.println[subject.getSubName[]]; } }

Output:

Java

Happy Learning