Example usage for java.util Random nextBytes

Introduction

In this page you can find the example usage for java.util Random nextBytes.

Prototype

public void nextBytes(byte[] bytes) 

Source Link

Document

Generates random bytes and places them into a user-supplied byte array.

Usage

From source file:Main.java

public static void main(String... a) {
    int n = 16;/*from  w ww  .ja  v a2  s.c  o  m*/

    Random r = new Random();
    byte[] b = new byte[n];
    r.nextBytes(b);
    BigInteger i = new BigInteger(b);

    System.out.println(i);
}

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From source file:Main.java

public static void main(String[] argv) throws Exception {

    Random rand = new Random();

    byte[] bytes = new byte[5];
    rand.nextBytes(bytes);
}

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From source file:Main.java

public static void main(String args[]) {

    Random randomno = new Random();

    // create byte array
    byte[] nbyte = new byte[30];

    // put the next byte in the array
    randomno.nextBytes(nbyte);

    // check the value of array   
    System.out.println("Value of byte array: " + Arrays.toString(nbyte));
}

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From source file:org.helios.rindle.metric.MetricSerialization.java

public static void main(String[] args) {
    log("Test Metric Ser");
    byte[] okey = new byte[10];
    Random r = new Random(System.currentTimeMillis());
    r.nextBytes(okey);
    IMetricDefinition[] metrics = {/*from   ww  w . ja  v  a2s  . com*/

            new UnsafeMetricDefinition(77, "MeToo", okey),
            new UnsafeMetricDefinition(54, "FooBar", "FooBar".getBytes()) };

    //      SimpleModule module = new SimpleModule();
    //      module.addSerializer(IMetricDefinition.class, new MetricSerialization.UnsafeMetricDefinitionSerializer());
    //      module.addDeserializer(IMetricDefinition.class, new MetricSerialization.UnsafeMetricDefinitionDeserializer());
    //      MAP.registerModule(module);
    try {
        String s = JSON.MAP.writeValueAsString(metrics);
        log(s);
        //         String text = "[{\"id\":54,\"ts\":1397644799993,\"n\":\"FooBar\",\"o\":\"Um05dlFtRnk=\"},{\"id\":77,\"ts\":1397644799993,\"n\":\"MeToo\",\"o\":\"V1c5NWJ3PT0A\"}]";
        IMetricDefinition[] deser = JSON.MAP.readValue(s, IMetricDefinition[].class);
        log(Arrays.toString(deser));
        log("========================================");
        s = JSON.MAP.writeValueAsString(deser);
        log(s);
        log("========================================");
        for (int i = 0; i < deser.length; i++) {
            log("Metric 1:" + deser[i].equals(metrics[i]));
        }
    } catch (Exception x) {
        x.printStackTrace(System.err);
    }
    //      MAP.registerModule(mod);
}

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From source file:HashCollider.java

/**i
 * @param args the command line arguments
 *///from  www.j a  va2s .c om
public static void main(String[] args) {
    Random random = new Random();
    byte[] nbytes1 = new byte[64];
    byte[] nbytes2 = new byte[64];
    float average = 0;
    // set number of bits for checking collision
    int number_of_bits = 4;
    random.nextBytes(nbytes1);
    random.nextBytes(nbytes2);

    String sha1 = DigestUtils.sha256Hex(nbytes1);
    String sha2 = DigestUtils.sha256Hex(nbytes2);

    String nsh1 = new BigInteger(sha1, 16).toString(2);
    String nsh2 = new BigInteger(sha2, 16).toString(2);
    int i = 0;
    for (int j = 0; j < 5; j++) {
        while (true) {
            if (nsh1.substring(0, number_of_bits - 1).equals(nsh2.substring(0, number_of_bits - 1))) {
                System.out.println(i);
                average += i;
                break;
            }
            i++;
            //            System.out.println("......"+i);
            random.nextBytes(nbytes1);
            random.nextBytes(nbytes2);
            sha1 = DigestUtils.sha256Hex(nbytes1);
            sha2 = DigestUtils.sha256Hex(nbytes2);
            nsh1 = new BigInteger(sha1, 16).toString(2);
            nsh2 = new BigInteger(sha2, 16).toString(2);
        }
        i = 0;
        //        System.out.println(nsh1+"\n"+nsh2);
        random.nextBytes(nbytes1);
        random.nextBytes(nbytes2);
        sha1 = DigestUtils.sha256Hex(nbytes1);
        sha2 = DigestUtils.sha256Hex(nbytes2);
        nsh1 = new BigInteger(sha1, 16).toString(2);
        nsh2 = new BigInteger(sha2, 16).toString(2);

    }
    //
    System.out.println("Average for  " + number_of_bits + " bits is  " + average / 5);

}

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From source file:org.apache.hadoop.hbase.regionserver.TestPerColumnFamilyFlush.java

public static void main(String[] args) throws Exception {
    int numRegions = Integer.parseInt(args[0]);
    long numRows = Long.parseLong(args[1]);

    HTableDescriptor htd = new HTableDescriptor(TABLENAME);
    htd.setMaxFileSize(10L * 1024 * 1024 * 1024);
    htd.setValue(HTableDescriptor.SPLIT_POLICY, ConstantSizeRegionSplitPolicy.class.getName());
    htd.addFamily(new HColumnDescriptor(FAMILY1));
    htd.addFamily(new HColumnDescriptor(FAMILY2));
    htd.addFamily(new HColumnDescriptor(FAMILY3));

    Configuration conf = HBaseConfiguration.create();
    Connection conn = ConnectionFactory.createConnection(conf);
    Admin admin = conn.getAdmin();//from w  w  w  . j  av a 2s. c  om
    if (admin.tableExists(TABLENAME)) {
        admin.disableTable(TABLENAME);
        admin.deleteTable(TABLENAME);
    }
    if (numRegions >= 3) {
        byte[] startKey = new byte[16];
        byte[] endKey = new byte[16];
        Arrays.fill(endKey, (byte) 0xFF);
        admin.createTable(htd, startKey, endKey, numRegions);
    } else {
        admin.createTable(htd);
    }
    admin.close();

    Table table = conn.getTable(TABLENAME);
    byte[] qf = Bytes.toBytes("qf");
    Random rand = new Random();
    byte[] value1 = new byte[16];
    byte[] value2 = new byte[256];
    byte[] value3 = new byte[4096];
    for (long i = 0; i < numRows; i++) {
        Put put = new Put(Hashing.md5().hashLong(i).asBytes());
        rand.setSeed(i);
        rand.nextBytes(value1);
        rand.nextBytes(value2);
        rand.nextBytes(value3);
        put.addColumn(FAMILY1, qf, value1);
        put.addColumn(FAMILY2, qf, value2);
        put.addColumn(FAMILY3, qf, value3);
        table.put(put);
        if (i % 10000 == 0) {
            LOG.info(i + " rows put");
        }
    }
    table.close();
    conn.close();
}

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From source file:org.opendedup.collections.ShardedProgressiveFileBasedCSMap.java

public static void main(String[] args) throws Exception {
    ShardedProgressiveFileBasedCSMap b = new ShardedProgressiveFileBasedCSMap();
    b.init(1000000, "/opt/sdfs/hash", .001);
    long start = System.currentTimeMillis();
    Random rnd = new Random();
    byte[] hash = null;
    long val = -33;
    byte[] hash1 = null;
    long val1 = -33;
    Tiger16HashEngine eng = new Tiger16HashEngine();
    for (int i = 0; i < 60000; i++) {
        byte[] z = new byte[64];
        rnd.nextBytes(z);
        hash = eng.getHash(z);/* ww w. j  av  a  2s .  com*/
        val = rnd.nextLong();
        if (i == 1) {
            val1 = val;
            hash1 = hash;
        }
        if (val < 0)
            val = val * -1;
        ChunkData cm = new ChunkData(hash, val);
        InsertRecord k = b.put(cm);
        if (k.getInserted())
            System.out.println("Unable to add this " + k);

    }
    long end = System.currentTimeMillis();
    System.out.println("Took " + (end - start) / 1000 + " s " + val1);
    System.out.println("Took " + (System.currentTimeMillis() - end) / 1000 + " ms at pos " + b.get(hash1));
    b.claimRecords(SDFSEvent.gcInfoEvent("testing 123"));
    b.close();

}

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From source file:Main.java

private static ByteBuffer buffer(int len) {
    byte[] b = new byte[len];
    Random r = new Random();
    r.nextBytes(b);
    return ByteBuffer.wrap(b);
}

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From source file:MainClass.java

private static String encrypt(char[] password, String plaintext) throws Exception {

    byte[] salt = new byte[8];
    Random random = new Random();
    random.nextBytes(salt);

    PBEKeySpec keySpec = new PBEKeySpec(password);

    SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithSHAAndTwofish-CBC");

    SecretKey key = keyFactory.generateSecret(keySpec);

    PBEParameterSpec paramSpec = new PBEParameterSpec(salt, 1000);

    Cipher cipher = Cipher.getInstance("PBEWithSHAAndTwofish-CBC");
    cipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);

    byte[] ciphertext = cipher.doFinal(plaintext.getBytes());

    BASE64Encoder encoder = new BASE64Encoder();

    String saltString = encoder.encode(salt);
    String ciphertextString = encoder.encode(ciphertext);

    return saltString + ciphertextString;
}

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From source file:com.pamarin.income.util.StringRandom.java

public static String random2048bit() {
    byte[] r = new byte[256]; //Means 2048 bit
    Random random = new Random();
    random.nextBytes(r);

    return Base64.encodeBase64String(r).replace("+", "_");
}

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