StringBuffer ensureCapacity() method in Java with Examples Last Updated : 28 Dec, 2022 Comments Improve Suggest changes Like Article Like Report The ensureCapacity() method of StringBuffer class ensures the capacity to at least equal to the specified minimumCapacity. If the current capacity of StringBuffer < the argument minimumCapacity, then a new internal array is allocated with greater capacity.If the minimumCapacity argument > twice the old capacity, plus 2 then new capacity is equal to minimumCapacity else new capacity is equal to twice the old capacity, plus 2.If the minimumCapacity argument passed as parameter < 0, this method takes no action. Syntax: public void ensureCapacity(int minimumCapacity) Parameters: This method takes one parameter minimumCapacity which is the minimum desired capacity. Return Value: This method do not return anything. Below programs demonstrate the ensureCapacity() method of StringBuffer Class Example 1: Java // Java program to demonstrate // the ensureCapacity() Method. class GFG { public static void main(String[] args) { // create a StringBuffer object StringBuffer str = new StringBuffer(); // print string capacity System.out.println("Before ensureCapacity " + "method capacity = " + str.capacity()); // apply ensureCapacity() str.ensureCapacity(18); // print string capacity System.out.println("After ensureCapacity" + " method capacity = " + str.capacity()); } } Output:Before ensureCapacity method capacity = 16 After ensureCapacity method capacity = 34 Example 2: Java // Java program to demonstrate // the ensureCapacity() Method. class GFG { public static void main(String[] args) { // create a StringBuffer object StringBuffer str = new StringBuffer("Geeks For Geeks"); // print string capacity System.out.println("Before ensureCapacity " + "method capacity = " + str.capacity()); // apply ensureCapacity() str.ensureCapacity(42); // print string capacity System.out.println("After ensureCapacity" + " method capacity = " + str.capacity()); } } Output:Before ensureCapacity method capacity = 31 After ensureCapacity method capacity = 64 References: https://docs.oracle.com/javase/10/docs/api/java/lang/StringBuffer.html#ensureCapacity(int) Comment More infoAdvertise with us A AmanSingh2210 Follow Improve Article Tags : Java java-basics Java-Functions java-StringBuffer Practice Tags : Java Explore BasicsIntroduction to Java4 min readJava Programming Basics9 min readJava Methods7 min readAccess Modifiers in Java6 min readArrays in Java9 min readJava Strings8 min readRegular Expressions in Java7 min readOOP & InterfacesClasses and Objects in Java10 min readJava Constructors10 min readJava OOP(Object Oriented Programming) Concepts10 min readJava Packages7 min readJava Interface11 min readCollectionsCollections in Java12 min readCollections Class in Java13 min readCollection Interface in Java6 min readIterator in Java5 min readJava Comparator Interface6 min readException HandlingJava Exception Handling8 min readJava Try Catch Block4 min readJava final, finally and finalize4 min readChained Exceptions in Java3 min readNull Pointer Exception in Java5 min readException Handling with Method Overriding in Java4 min readJava AdvancedJava Multithreading Tutorial3 min readSynchronization in Java10 min readFile Handling in Java4 min readJava Method References9 min readJava 8 Stream Tutorial15+ min readJava Networking15+ min readJDBC Tutorial12 min readJava Memory Management4 min readGarbage Collection in Java6 min readMemory Leaks in Java3 min readPractice JavaJava Interview Questions and Answers15+ min readJava Programs - Java Programming Examples8 min readJava Exercises - Basic to Advanced Java Practice Programs with Solutions7 min readJava Quiz | Level Up Your Java Skills1 min readTop 50 Java Project Ideas For Beginners and Advanced [Update 2025]15+ min read Like