diff --git a/crawler4j/src/main/java/edu/uci/ics/crawler4j/util/Util.java b/crawler4j/src/main/java/edu/uci/ics/crawler4j/util/Util.java
index 2a4923bb0..679266271 100644
--- a/crawler4j/src/main/java/edu/uci/ics/crawler4j/util/Util.java
+++ b/crawler4j/src/main/java/edu/uci/ics/crawler4j/util/Util.java
@@ -58,10 +58,10 @@ public static int byteArray2Int(byte[] b) {
     }
 
     public static long byteArray2Long(byte[] b) {
-        int value = 0;
+        long value = 0;
         for (int i = 0; i < 8; i++) {
             int shift = (8 - 1 - i) * 8;
-            value += (b[i] & 0x000000FF) << shift;
+            value += (b[i] & 0x000000FFL) << shift;
         }
         return value;
     }
diff --git a/crawler4j/src/test/java/edu/uci/ics/crawler4j/tests/util/UtilTest.java b/crawler4j/src/test/java/edu/uci/ics/crawler4j/tests/util/UtilTest.java
new file mode 100644
index 000000000..2e6f71dde
--- /dev/null
+++ b/crawler4j/src/test/java/edu/uci/ics/crawler4j/tests/util/UtilTest.java
@@ -0,0 +1,108 @@
+package edu.uci.ics.crawler4j.util;
+
+import org.junit.Assert;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.Timeout;
+
+public class UtilTest {
+
+    @Rule
+    public final Timeout globalTimeout = new Timeout(10000);
+
+    /* testedClasses: Util */
+    // Test written by Diffblue Cover.
+    @Test
+    public void long2ByteArray() {
+
+        // Arrange
+        final long l = 0x12ff34ff56ffL;
+
+        // Act
+        final byte[] actual = Util.long2ByteArray(l);
+
+        // Assert result
+        Assert.assertArrayEquals(
+            new byte[] {0, 0, 0x12, -1, 0x34, -1, 0x56, -1}, actual);
+    }
+
+    // Test written by Diffblue Cover.
+    @Test
+    public void int2ByteArray() {
+
+        // Arrange
+        final int value = 0x12ff34ff;
+
+        // Act
+        final byte[] actual = Util.int2ByteArray(value);
+
+        // Assert result
+        Assert.assertArrayEquals(new byte[] {0x12, -1, 0x34, -1}, actual);
+    }
+
+    // Test written by Diffblue Cover.
+    @Test
+    public void putIntInByteArray() {
+
+        // Arrange
+        final int value = 0x12ff34ff;
+        final byte[] buf = {0, 0, 0, 0, 0, 0};
+        final int offset = 2;
+
+        // Act
+        Util.putIntInByteArray(value, buf, offset);
+
+        // Assert side effects
+        Assert.assertArrayEquals(new byte[] {0, 0, 0x12, -1, 0x34, -1}, buf);
+    }
+
+    // Test written by Diffblue Cover.
+    @Test
+    public void byteArray2Int() {
+
+        // Arrange
+        final byte[] b = {0x12, -1, 0x34, -1};
+
+        // Act
+        final int actual = Util.byteArray2Int(b);
+
+        // Assert result
+        Assert.assertEquals(0x12ff34ff, actual);
+    }
+
+    // Test written by Diffblue Cover.
+    @Test
+    public void byteArray2Long() {
+
+        // Arrange
+        final byte[] b = {0, 0, 0, -1, 0x34, -1, 0x56, -1};
+
+        // Act
+        final long actual = Util.byteArray2Long(b);
+
+        // Assert result
+        Assert.assertEquals(0x0ff34ff56ffL, actual);
+    }
+
+    // Test written by Diffblue Cover.
+    @Test
+    public void hasBinaryContent() {
+        Assert.assertFalse(Util.hasBinaryContent("BAZ"));
+        Assert.assertTrue(Util.hasBinaryContent("hhhYaimage"));
+    }
+
+    // Test written by Diffblue Cover.
+    @Test
+    public void hasPlainTextContent() {
+        Assert.assertFalse(Util.hasPlainTextContent("1"));
+        Assert.assertFalse(Util.hasPlainTextContent("htmlTTeXT"));
+        Assert.assertTrue(Util.hasPlainTextContent("YxtEXTeXT"));
+    }
+
+    // Test written by Diffblue Cover.
+    @Test
+    public void hasCssTextContentOutputFalse() {
+        Assert.assertFalse(Util.hasCssTextContent("1234"));
+    }
+
+}