Sorting collection of String and StringBuffer in Java Last Updated : 09 Nov, 2020 Summarize Comments Improve Suggest changes Share Like Article Like Report Sorting a collection of objects can be done in two ways: By implementing Comparable (Natural Order) e.g. Strings are sorted ASCIIbetically. meaning B comes before A and 10 is before 2.By implementing Comparator (Custom order) and it can be in any order.Using Collections.sort() method of Collections utility class. Read more about Comparable and ComparatorFor sorted Collection we can use below collections: TreeSetTreeMap In case of String, sorting will be done automatically in natural order. Java // Java program to sort String objects using TreeSet import java.util.Set; import java.util.TreeSet; public class Test { public static void main(String[] args) { Set<String> str = new TreeSet<String>(); str.add("Sohan"); str.add("Raja"); str.add("Harish"); str.add("Ram"); System.out.println(str); } } Output: [Harish, Raja, Ram, Sohan] Java // Java program to demonstrate that simple sorting // StringBuffer objects does work. import java.util.Set; import java.util.TreeSet; public class Test { public static void main(String[] args) { Set<StringBuffer> str = new TreeSet<>(); str.add(new StringBuffer("Sohan")); str.add(new StringBuffer("Raja")); str.add(new StringBuffer("Harish")); str.add(new StringBuffer("Ram")); System.out.println(str); } } Output[Harish, Raja, Ram, Sohan] String class implements Comparable interface whereas StringBuffer and StringBuilder classes do not implement Comparable interface. See below signatures of String, StringBuffer and StringBuilder classes: Java public final class String extends Object implements Serializable, Comparable, CharSequence Java public final class StringBuffer extends Object implements Serializable, CharSequence Java public final class StringBuilder extends Object implements Serializable, CharSequence There are many ways of sorting StringBuffer, StringBuilder classes. Some of the ways are given below: By implementing Comparator interfaceBy converting StringBuffer to String using StringBuffer.toString() method Java // Java program to demonstrate sorting // of StringBuffer objects using Comparator // interface. import java.util.Comparator; import java.util.Set; import java.util.TreeSet; public class Test implements Comparator<StringBuffer> { @Override public int compare(StringBuffer s1, StringBuffer s2) { return s1.toString().compareTo(s2.toString()); } public static void main(String[] args) { Set<StringBuffer> str = new TreeSet<>(new Test()); str.add(new StringBuffer("Sohan")); str.add(new StringBuffer("Raja")); str.add(new StringBuffer("Harish")); str.add(new StringBuffer("Ram")); System.out.println(str); } } Output: [Harish, Raja, Ram, Sohan] Comment More infoAdvertise with us Next Article How to sort an Array of Strings in Java S sajid.hmdrd Improve Article Tags : Java Java-Strings java-StringBuffer Java-String-Programs Practice Tags : JavaJava-Strings Similar Reads equals() on String and StringBuffer objects in Java Consider the following codes in java: Java // This program prints false class GFG { public static void main(String[] args) { StringBuffer sb1 = new StringBuffer("GFG"); StringBuffer sb2 = new StringBuffer("GFG"); System.out.println(sb1.equals(sb2)); } } Output: false Java // This 1 min read How to sort an Array of Strings in Java Array Of StringsTo sort an array of strings in Java, we can use Arrays.sort() function. Java // A sample Java program to // sort an array of strings // in ascending and descending // orders using Arrays.sort(). import java.util.Arrays; import java.util.Collections; // Driver Class public class SortE 3 min read How to sort an Array of Strings in Java Array Of StringsTo sort an array of strings in Java, we can use Arrays.sort() function. Java // A sample Java program to // sort an array of strings // in ascending and descending // orders using Arrays.sort(). import java.util.Arrays; import java.util.Collections; // Driver Class public class SortE 3 min read Swapping Pairs of Characters in a String in Java Given string str, the task is to write a Java program to swap the pairs of characters of a string. If the string contains an odd number of characters then the last character remains as it is. Examples: Input: str = “Javaâ€Output: aJav Explanation: The given string contains even number of characters. 3 min read String vs StringBuilder vs StringBuffer in Java A string is a sequence of characters. In Java, String objects are immutable, which simply means once created, their values can not be changed. In Java, String, StringBuilder, and StringBuffer are used for handling strings. The main difference is:String: Immutable, meaning its value cannot be changed 6 min read String vs StringBuilder vs StringBuffer in Java A string is a sequence of characters. In Java, String objects are immutable, which simply means once created, their values can not be changed. In Java, String, StringBuilder, and StringBuffer are used for handling strings. The main difference is:String: Immutable, meaning its value cannot be changed 6 min read Like