Change Checksum to use CRC32

ebean-core/src/main/java/io/ebeaninternal/server/util/Checksum.java

@@ -1,7 +1,7 @@
 package io.ebeaninternal.server.util;
 
 import java.nio.charset.StandardCharsets;
-import java.util.zip.Adler32;
+import java.util.zip.CRC32;
 
 /**
  * Compute a checksum for String content. Use when we desire cheaper option than MD5.
@@ -12,9 +12,9 @@ public final class Checksum {
    * Return the checksum for the given String input.
    */
   public static long checksum(String input) {
-    Adler32 adler32 = new Adler32();
+    CRC32 checksum = new CRC32();
     final byte[] bytes = input.getBytes(StandardCharsets.UTF_8);
-    adler32.update(bytes, 0, bytes.length);
-    return adler32.getValue();
+    checksum.update(bytes, 0, bytes.length);
+    return checksum.getValue();
   }
 }

ebean-core/src/test/java/io/ebeaninternal/server/util/ChecksumTest.java

@@ -8,11 +8,16 @@ public class ChecksumTest {
 
   @Test
   public void checksum() {
-
     final long val = Checksum.checksum("Hello world");
-    assertThat(val).isEqualTo(413860925L);
-
+    assertThat(val).isEqualTo(2346098258L);
     assertThat(Checksum.checksum("Hello world")).isEqualTo(val);
     assertThat(Checksum.checksum("hello world")).isNotEqualTo(val);
   }
+
+  @Test
+  public void checksum_shortString() {
+    final long val0 = Checksum.checksum("2012-01-11");
+    final long val1 = Checksum.checksum("2012-10-02");
+    assertThat(val0).isNotEqualTo(val1);
+  }
 }