diff --git a/openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/criteria/TestTypesafeCriteria.java b/openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/criteria/TestTypesafeCriteria.java
index ff0c0bdec..4af5dd23c 100644
--- a/openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/criteria/TestTypesafeCriteria.java
+++ b/openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/criteria/TestTypesafeCriteria.java
@@ -25,6 +25,7 @@ import org.apache.openjpa.persistence.test.SQLListenerTestCase;
  */
 public class TestTypesafeCriteria extends SQLListenerTestCase {
     CriteriaBuilder cb;
+    CriteriaQuery c;
     EntityManager em;
     
     public void setUp() {
@@ -32,6 +33,8 @@ public class TestTypesafeCriteria extends SQLListenerTestCase {
         setDictionary();
         cb = (CriteriaBuilder)emf.getQueryBuilder();
         em = emf.createEntityManager();
+        
+        c = cb.create();
     }
     
     void setDictionary() {
@@ -50,6 +53,14 @@ public class TestTypesafeCriteria extends SQLListenerTestCase {
         assertEquivalence(c, jpql);
     }
     
+    public void testImplicitRoot() {
+    	String jpql = "select a from Account a";
+        CriteriaQuery c = cb.create();
+        c.from(Account.class);
+        
+        assertEquivalence(c, jpql);
+    }
+    
     public void testEqual() {
     	String jpql = "select a from Account a where a.balance=100";
     	
@@ -98,6 +109,13 @@ public class TestTypesafeCriteria extends SQLListenerTestCase {
         assertEquivalence(c, jpql);
     }
 
+    public void testInPredicate() {
+    	String jpql = "select a from Account a where a.owner in ('X','Y','Z')";
+        CriteriaQuery c = cb.create();
+        Root<Account> account = c.from(Account.class);
+        c.where(cb.in(account.get(Account_.owner)).value("X").value("Y").value("Z"));
+        assertEquivalence(c, jpql);
+    }
     
     public void testBinaryPredicate() {
     	String jpql = "select a from Account a where a.balance>100 and a.balance<200";
diff --git a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/ExpressionImpl.java b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/ExpressionImpl.java
index 731ed9c1f..f9c17429d 100644
--- a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/ExpressionImpl.java
+++ b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/ExpressionImpl.java
@@ -23,6 +23,7 @@ import java.util.Collection;
 
 import javax.persistence.criteria.Expression;
 import javax.persistence.criteria.Predicate;
+import javax.persistence.criteria.QueryBuilder.In;
 
 import org.apache.openjpa.kernel.exps.ExpressionFactory;
 import org.apache.openjpa.kernel.exps.Value;
@@ -60,32 +61,37 @@ public abstract class ExpressionImpl<X> extends SelectionImpl<X>
     }
 
     public Predicate in(Object... values) {
-        // TODO Auto-generated method stub
-        throw new AbstractMethodError();
+        In<X> result = new Expressions.In<X>(this);
+        for (Object v : values)
+        	result.value((X)v);
+        return result;
     }
 
     public Predicate in(Expression<?>... values) {
-        // TODO Auto-generated method stub
-        throw new AbstractMethodError();
+        In<X> result = new Expressions.In<X>(this);
+        for (Expression<?> e : values)
+        	result.value((Expression<? extends X>)e);
+        return result;
     }
 
     public Predicate in(Collection<?> values) {
-        // TODO Auto-generated method stub
-        throw new AbstractMethodError();
+        In<X> result = new Expressions.In<X>(this);
+        for (Object e : values)
+        	result.value((X)e);
+        return result;
     }
 
     public Predicate in(Expression<?> values) {
-        // TODO Auto-generated method stub
-        throw new AbstractMethodError();
+        In<X> result = new Expressions.In<X>(this);
+        result.value((Expression<? extends X>)values);
+        return result;
     }
 
     public Predicate isNotNull() {
-        // TODO Auto-generated method stub
-        throw new AbstractMethodError();
+    	return new Expressions.IsNotNull(this);
     }
 
     public Predicate isNull() {
-        // TODO Auto-generated method stub
-        throw new AbstractMethodError();
+    	return new Expressions.IsNull(this);
     }
 }
diff --git a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/Expressions.java b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/Expressions.java
index 43ea0a5f3..bba278004 100644
--- a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/Expressions.java
+++ b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/Expressions.java
@@ -24,6 +24,7 @@ import java.util.Collection;
 import java.util.List;
 
 import javax.persistence.criteria.Expression;
+import javax.persistence.criteria.Predicate;
 import javax.persistence.criteria.QueryBuilder;
 import javax.persistence.criteria.QueryBuilder.Trimspec;
 
@@ -700,12 +701,45 @@ public class Expressions {
         }
     }
     
-    public static class In<T> extends PredicateImpl 
+    public static class IsNull extends PredicateImpl {
+    	ExpressionImpl<?> e;
+    	public IsNull(ExpressionImpl<?> e) {
+    		super();
+    		this.e = e;
+    	}
+    	
+    	@Override
+        org.apache.openjpa.kernel.exps.Expression toKernelExpression(
+            ExpressionFactory factory, MetamodelImpl model) {
+    		return factory.equal(
+    			Expressions.toValue(e, factory, model), 
+    			factory.getNull());
+    	}
+    }
+    
+    public static class IsNotNull extends PredicateImpl {
+    	ExpressionImpl<?> e;
+    	public IsNotNull(ExpressionImpl<?> e) {
+    		super();
+    		this.e = e;
+    	}
+    	
+    	@Override
+        org.apache.openjpa.kernel.exps.Expression toKernelExpression(
+            ExpressionFactory factory, MetamodelImpl model) {
+    		return factory.notEqual(
+    			Expressions.toValue(e, factory, model), 
+    			factory.getNull());
+    	}
+    }
+    
+    
+    public static class In<T> extends PredicateImpl.Or 
     	implements QueryBuilder.In<T> {
-    	private List<Expression<? extends T>> values = 
-    		new ArrayList<Expression<? extends T>>();
+    	ExpressionImpl<?> e;
     	public In(Expression<?> e) {
-    		super(null);
+    		super((Predicate[])null);
+    		this.e = (ExpressionImpl<?>)e;
     	}
     	
     	public Expression<T> getExpression() {
@@ -713,12 +747,22 @@ public class Expressions {
     	}
 
     	public In<T> value(T value) {
-        	return value(new Constant<T>(value));
+    		add(new Expressions.Equal(e,value));
+        	return this;
     	}
 
     	public In<T> value(Expression<? extends T> value) {
-        	values.add(value); 
+    		add(new Expressions.Equal(e,value));
         	return this;
     	}
+    
+    	@Override
+        org.apache.openjpa.kernel.exps.Expression toKernelExpression(
+            ExpressionFactory factory, MetamodelImpl model) {
+    		IsNotNull notNull = new Expressions.IsNotNull(e);
+    		return factory.and(
+     		    super.toKernelExpression(factory, model),
+    		    notNull.toKernelExpression(factory, model));
+    	}
     }
 }
diff --git a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/PredicateImpl.java b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/PredicateImpl.java
index e7a9b7a05..2aafa9492 100644
--- a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/PredicateImpl.java
+++ b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/criteria/PredicateImpl.java
@@ -44,8 +44,10 @@ public class PredicateImpl extends ExpressionImpl<Boolean>
     
     protected PredicateImpl(BooleanOperator op, Predicate...restrictions) {
 		this(op);
-		for (Predicate p : restrictions)
-			add((PredicateImpl)p);
+		if (restrictions != null) {
+			for (Predicate p : restrictions)
+				add((PredicateImpl)p);
+		}
 	}
 
     public PredicateImpl add(Expression<Boolean> s) {
@@ -70,7 +72,8 @@ public class PredicateImpl extends ExpressionImpl<Boolean>
     public PredicateImpl negate() {
         PredicateImpl not = new PredicateImpl(_op);
         not._negated = true;
-        not._exps = new ArrayList<Expression<Boolean>>(this._exps);
+        if (_exps != null)
+        	not._exps = new ArrayList<Expression<Boolean>>(this._exps);
         not._op = this._op;
         return not;
     }
@@ -90,13 +93,14 @@ public class PredicateImpl extends ExpressionImpl<Boolean>
     		org.apache.openjpa.kernel.exps.Expression ke2 = 
     			e2.toKernelExpression(factory, model);
     		org.apache.openjpa.kernel.exps.Expression result = 
-    			_op == BooleanOperator.AND ?
-    			factory.and(ke1,ke2) : factory.or(ke1, ke2);
+    			_op == BooleanOperator.AND 
+    			? factory.and(ke1,ke2) : factory.or(ke1, ke2);
 
     		for (int i = 2; i < _exps.size(); i++) {
     			ExpressionImpl<?> e = (ExpressionImpl<?>)_exps.get(i);
-    			result = factory.and(result, 
-    				e.toKernelExpression(factory, model));
+    			result = _op == BooleanOperator.AND 
+                ? factory.and(result, e.toKernelExpression(factory, model))
+    		    : factory.or(result, e.toKernelExpression(factory, model));
     		}
     		return _negated ? factory.not(result) : result;
     }
@@ -119,7 +123,7 @@ public class PredicateImpl extends ExpressionImpl<Boolean>
     	}
     	
     	public Or(Predicate...restrictions) {
-    		super(BooleanOperator.AND, restrictions);
+    		super(BooleanOperator.OR, restrictions);
     	}
     }
 }