Don't initialize an instance or static variable to its default value

src/conf/checkstyle/checkstyle.xml

@@ -59,6 +59,7 @@
 
   <module name="TreeWalker">
 
+    <module name="ExplicitInitializationCheck" />
     <!-- ************************************************************** -->
     <!-- Checks that are different from the sun coding conventions ones -->
     <!-- ************************************************************** -->

src/main/java/org/apache/commons/dbutils/AbstractQueryRunner.java

@@ -44,7 +44,7 @@ public abstract class AbstractQueryRunner {
      * Is {@link ParameterMetaData#getParameterType(int)} broken (have we tried
      * it yet)?
      */
-    private volatile boolean pmdKnownBroken = false;
+    private volatile boolean pmdKnownBroken;
 
     /**
      * The DataSource to retrieve connections from.

src/main/java/org/apache/commons/dbutils/OutParameter.java

@@ -36,7 +36,7 @@
 public class OutParameter<T> {
     private final int sqlType;
     private final Class<T> javaType;
-    private T value = null;
+    private T value;
 
     /**
      * Construct an {@code OutParameter} for the given JDBC SQL type and

src/test/java/org/apache/commons/dbutils/BaseTestCase.java

@@ -103,12 +103,12 @@ public class BaseTestCase extends TestCase {
     /**
      * The ResultSet all test methods will use.
      */
-    protected ResultSet rs = null;
+    protected ResultSet rs;
 
     /**
      * A ResultSet with 0 rows.
      */
-    protected ResultSet emptyResultSet = null;
+    protected ResultSet emptyResultSet;
 
     /**
      * Creates a freshly initialized ResultSet.

src/test/java/org/apache/commons/dbutils/MockResultSet.java

@@ -48,9 +48,9 @@ public static ResultSet create(final ResultSetMetaData metaData,
 
     private Object[] currentRow = null;
 
-    private Iterator<Object[]> iter = null;
+    private Iterator<Object[]> iter;
 
-    private ResultSetMetaData metaData = null;
+    private ResultSetMetaData metaData;
 
     private Boolean wasNull = Boolean.FALSE;
 

src/test/java/org/apache/commons/dbutils/TestBean.java

@@ -27,17 +27,17 @@ public enum Ordinal {
 
     }
 
-    private String one = null;
+    private String one;
 
-    private String two = null;
+    private String two;
 
-    private Ordinal three = null;
+    private Ordinal three;
 
-    private int intTest = 0;
+    private int intTest;
 
     private Integer integerTest = Integer.valueOf(0);
 
-    // UNUSED private Timestamp timestamp = null;
+    // UNUSED private Timestamp timestamp;
 
     private String doNotSet = "not set";
 

src/test/java/org/apache/commons/dbutils/wrappers/SqlNullCheckedResultSetTest.java

@@ -230,7 +230,7 @@ private static void assertArrayEquals(final byte[] expected, final byte[] actual
         }
     }
 
-    private SqlNullCheckedResultSet rs2 = null;
+    private SqlNullCheckedResultSet rs2;
 
     /**
      * Sets up instance variables required by this test case.