test/jdk/java/nio/Buffer/AllocateDirectInit.java

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/**
 * @test
 * @bug 4490253 6535542 8357959
 * @key randomness
 * @library /test/lib
 * @build jdk.test.lib.RandomFactory
 * @summary Verify that newly allocated direct buffers are initialized.
 * @run main/othervm AllocateDirectInit
 */

import java.nio.ByteBuffer;
import java.util.Random;

import jdk.test.lib.RandomFactory;

public class AllocateDirectInit {
    private static final int MAX_BIN_LIMIT = 16 * 1024 * 1024;
    private static final int MAX_DEC_LIMIT = 10 * 1000 * 1000;
    private static final int TRIES_PER_LIMIT = 1024;

    private static final Random RND = RandomFactory.getRandom();

    public static void main(String [] args){
        // Try power of two limits
        for (int limit = 1; limit < MAX_BIN_LIMIT; limit *= 2) {
            check(ByteBuffer.allocateDirect(limit - 1));
            check(ByteBuffer.allocateDirect(limit));
            check(ByteBuffer.allocateDirect(limit + 1));
        }

        // Try power of ten limits
        for (int limit = 1; limit < MAX_DEC_LIMIT; limit *= 10) {
            check(ByteBuffer.allocateDirect(limit - 1));
            check(ByteBuffer.allocateDirect(limit));
            check(ByteBuffer.allocateDirect(limit + 1));
        }

        // Try random sizes within power of two limits
        for (int limit = 1; limit < MAX_BIN_LIMIT; limit *= 2) {
            for (int t = 0; t < TRIES_PER_LIMIT; t++) {
                check(ByteBuffer.allocateDirect(RND.nextInt(limit)));
            }
        }
    }

    private static void check(ByteBuffer bb) {
        while (bb.hasRemaining()) {
            if (bb.get() != 0) {
                int mismatchPos = bb.position();
                System.out.print("byte [");
                for (bb.position(0); bb.position() < bb.limit(); ) {
                    System.out.print(" " + Integer.toHexString(bb.get() & 0xff));
                }
                System.out.println(" ]");
                throw new RuntimeException("uninitialized buffer, position = " + mismatchPos);
            }
        }
    }
}