# ADR-0002 - Avoid using Java serialization

## Date

2012-12-01

## Context

In Gradle we often need to serialize in-memory objects for caching, or to transmit them across process barriers, etc.
Java serialization is one way to implement this, however, despite its simplicity of implementation, it has several drawbacks:

- **Performance:**
Java's built-in serialization mechanism is often slower compared to other serialization solutions.

    <_comment>UNIX CPIO Archive</_comment>
    <magic priority="50">
      <match value="070707" type="little16" offset="0"/>
      <match value="070707" type="big16" offset="0"/>
      <match value="070707" type="string" offset="0"/>
      <match value="070701" type="string" offset="0"/>
      <match value="070702" type="string" offset="0"/>
    </magic>
    <glob pattern="*.cpio"/>
  </mime-type>

        return "crawler.xml";
    }

    public void test_execute_web() throws Exception {
        final CrawlerWebServer server = new CrawlerWebServer(7070);
        server.start();

        final String url = "http://localhost:7070/";
        try {
            final int maxCount = 50;
            final int numOfThread = 10;

            final File file = File.createTempFile("crawler-", "");

            buf.append("<url>").append('\n');
            buf.append("<loc>http://localhost:7070/index.html</loc>").append('\n');
            buf.append("<loc>http://localhost:7070/file").append(count).append("-1.html").append("</loc>").append('\n');
            buf.append("</url>").append('\n');
            buf.append("</urlset>").append('\n');

    }

    public void test_execute_web() throws Exception {
        final CrawlerWebServer server = new CrawlerWebServer(7070);
        server.start();

        final String url = "http://localhost:7070/";
        try {
            final int maxCount = 50;
            final int numOfThread = 10;

            final File file = File.createTempFile("crawler-", "");

/**
 * Unit tests for {@link SipHashFunction}.
 *
 * @author Kurt Alfred Kluever
 */
public class SipHashFunctionTest extends TestCase {

  // From https://131002.net/siphash/siphash24.c
  // k = 00 01 02 ...
  private static final long K0 = 0x0706050403020100L;
  private static final long K1 = 0x0f0e0d0c0b0a0908L;
  private static final HashFunction SIP_WITH_KEY = Hashing.sipHash24(K0, K1);

/**
 * Unit tests for {@link SipHashFunction}.
 *
 * @author Kurt Alfred Kluever
 */
public class SipHashFunctionTest extends TestCase {

  // From https://131002.net/siphash/siphash24.c
  // k = 00 01 02 ...
  private static final long K0 = 0x0706050403020100L;
  private static final long K1 = 0x0f0e0d0c0b0a0908L;
  private static final HashFunction SIP_WITH_KEY = Hashing.sipHash24(K0, K1);

    AtomicDouble at = new AtomicDouble(+0.0);
    assertFalse(at.compareAndSet(-0.0, 7.0));
    assertFalse(at.weakCompareAndSet(-0.0, 7.0));
    assertBitEquals(+0.0, at.get());
    assertTrue(at.compareAndSet(+0.0, -0.0));
    assertBitEquals(-0.0, at.get());
    assertFalse(at.compareAndSet(+0.0, 7.0));
    assertFalse(at.weakCompareAndSet(+0.0, 7.0));
    assertBitEquals(-0.0, at.get());
  }

    .build();
client.newCall(newYorkTimesRequest).enqueue(new Callback() {
  ...
});
```

Running this race over home WiFi shows the Times (`0002`) completes just slightly sooner than the Post (`0001`):

```
0001 https://www.washingtonpost.com/
0001 0.000 callStart
0002 https://www.nytimes.com/
0002 0.000 callStart
0002 0.010 dnsStart
0001 0.013 dnsStart
0001 0.022 dnsEnd
0002 0.019 dnsEnd

      assertFalse(aa.compareAndSet(i, -0.0, 7.0));
      assertFalse(aa.weakCompareAndSet(i, -0.0, 7.0));
      assertBitEquals(+0.0, aa.get(i));
      assertTrue(aa.compareAndSet(i, +0.0, -0.0));
      assertBitEquals(-0.0, aa.get(i));
      assertFalse(aa.compareAndSet(i, +0.0, 7.0));
      assertFalse(aa.weakCompareAndSet(i, +0.0, 7.0));
      assertBitEquals(-0.0, aa.get(i));
    }
  }