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# Vector ensureCapacity() method in Java with Example

The ensureCapacity() method of Java.util.Vector class increases the capacity of this Vector instance, if necessary, to ensure that it can hold at least the number of elements specified by the minimum capacity argument.

Syntax:

`public void ensureCapacity(int minCapacity)`

Parameters: This method takes the desired minimum capacity as a parameter.

Below are the examples to illustrate the ensureCapacity() method.

Example 1:

 `// Java program to demonstrate``// ensureCapacity() method for Integer value`` ` `import` `java.util.*;`` ` `public` `class` `GFG1 {``    ``public` `static` `void` `main(String[] argv)``        ``throws` `Exception``    ``{`` ` `        ``try` `{`` ` `            ``// Creating object of Vector``            ``Vector``                ``vector = ``new` `Vector();`` ` `            ``// adding element to vector``            ``vector.add(``10``);``            ``vector.add(``20``);``            ``vector.add(``30``);``            ``vector.add(``40``);`` ` `            ``// Print the Vector``            ``System.out.println(``"Vector: "``                               ``+ vector);`` ` `            ``// ensure that the Vector``            ``// can hold upto 5000 elements``            ``// using ensureCapacity() method``            ``vector.ensureCapacity(``5000``);`` ` `            ``// Print``            ``System.out.println(``"Vector can now"``                               ``+ ``" surely store upto"``                               ``+ ``" 5000 elements."``);``        ``}`` ` `        ``catch` `(Exception e) {``            ``System.out.println(e);``        ``}``    ``}``}`

Output:

```Vector: [10, 20, 30, 40]
Vector can now surely store upto 5000 elements.
```

Example 2:

 `// Java program to demonstrate``// ensureCapacity() method for String value`` ` `import` `java.util.*;`` ` `public` `class` `GFG1 {``    ``public` `static` `void` `main(String[] argv)``        ``throws` `Exception``    ``{`` ` `        ``try` `{`` ` `            ``// Creating object of Vector``            ``Vector``                ``vector = ``new` `Vector();`` ` `            ``// adding element to vector``            ``vector.add(``"A"``);``            ``vector.add(``"B"``);``            ``vector.add(``"C"``);``            ``vector.add(``"D"``);`` ` `            ``// Print the Vector``            ``System.out.println(``"Vector: "``                               ``+ vector);`` ` `            ``// ensure that the Vector``            ``// can hold upto 400 elements``            ``// using ensureCapacity() method``            ``vector.ensureCapacity(``400``);`` ` `            ``// Print``            ``System.out.println(``"Vector can now"``                               ``+ ``" surely store upto"``                               ``+ ``" 400 elements."``);``        ``}`` ` `        ``catch` `(Exception e) {``            ``System.out.println(e);``        ``}``    ``}``}`

Output:

```Vector: [A, B, C, D]
Vector can now surely store upto 400 elements.
```

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