The allocate() method of java.nio.LongBuffer Class is used to allocate a new Long buffer next to the existing buffer. The new buffer’s position will be zero. Its limit will be its capacity. Its mark will be undefined. And each of its elements will be initialized to zero. It will have a backing array, and its array offset will be zero.
Syntax:Â
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public static LongBuffer allocate(Long capacity)
Parameter: This method takes the new buffer’s capacity, in Long, as a parameter.
Return Value: This method returns the new Long buffer.
Exception: This method throws the IllegalArgumentException if the capacity is a negative Longer.
Below programs illustrate the allocate() method:
Program 1:
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Java
// Java program to demonstrate// allocate() methodÂ
import java.nio.*;import java.util.*;Â
public class GFG {Â Â Â Â public static void main(String[] args)Â Â Â Â {Â
        // Declaring the capacity of the LongBuffer        int Capacity = 10;Â
        // Creating the LongBufferÂ
        // creating object of Longbuffer        // and allocating size capacity        LongBuffer ib = LongBuffer.allocate(Capacity);Â
        // putting the value in Longbuffer        ib.put(11);        ib.put(2, 19);Â
        System.out.println("LongBuffer: "                           + Arrays.toString(ib.array()));    }} |
Output:Â
LongBuffer: [11, 0, 19, 0, 0, 0, 0, 0, 0, 0]
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Program 2: To demonstrate IllegalArgumentException
Â
Java
// Java program to demonstrate// allocate() methodÂ
import java.nio.*;import java.util.*;Â
public class GFG {Â Â Â Â public static void main(String[] args)Â Â Â Â {Â
        // Declaring the capacity of the LongBuffer        // by negative Longer        int Capacity = -10;Â
        // Creating the LongBuffer        try {Â
            // creating object of Longbuffer            // and allocating size with negative Longer            System.out.println("Trying to allocate a Negative Longer");Â
            LongBuffer ib = LongBuffer.allocate(Capacity);        }        catch (IllegalArgumentException e) {            System.out.println("Exception thrown: " + e);        }    }} |
Output
Trying to allocate a Negative Longer Exception thrown: java.lang.IllegalArgumentException: capacity < 0: (-10 < 0)
