diff --git a/CHANGES.md b/CHANGES.md
index a468ab17f..2a5aa5156 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -7,6 +7,7 @@
  * [METAMODEL-1139] - Employed Java 8 functional types (java.util.function) in favor of (now deprecated) Ref, Action, Func. 
  * [METAMODEL-1140] - Allowed SalesforceDataContext without a security token.
  * [METAMODEL-1141] - Added RFC 4180 compliant CSV parsing.
+ * [METAMODEL-1144] - Optimized evaluation of conditional client-side JOIN statements.
 
 ### Apache MetaModel 4.6.0
 
diff --git a/core/src/main/java/org/apache/metamodel/MetaModelHelper.java b/core/src/main/java/org/apache/metamodel/MetaModelHelper.java
index f30a08aca..a2681da58 100644
--- a/core/src/main/java/org/apache/metamodel/MetaModelHelper.java
+++ b/core/src/main/java/org/apache/metamodel/MetaModelHelper.java
@@ -175,7 +175,7 @@ public static DataSet getCarthesianProduct(DataSet[] fromDataSets, FilterItem...
     }
 
     public static DataSet getCarthesianProduct(DataSet[] fromDataSets, Iterable<FilterItem> whereItems) {
-        assert(fromDataSets.length>0);
+        assert (fromDataSets.length > 0);
         // First check if carthesian product is even nescesary
         if (fromDataSets.length == 1) {
             return getFiltered(fromDataSets[0], whereItems);
@@ -185,76 +185,75 @@ public static DataSet getCarthesianProduct(DataSet[] fromDataSets, Iterable<Filt
 
         DataSet joined = dsIter.next();
 
-        while(dsIter.hasNext()){
-            joined = nestedLoopJoin(
-                    dsIter.next(),
-                    joined,
-                    (whereItems));
+        while (dsIter.hasNext()) {
+            joined = nestedLoopJoin(dsIter.next(), joined, (whereItems));
 
         }
 
         return joined;
 
-
     }
 
     /**
-     * Executes a simple nested loop join. The innerLoopDs will be copied in an in-memory dataset.
+     * Executes a simple nested loop join. The innerLoopDs will be copied in an
+     * in-memory dataset.
      *
      */
-    public static InMemoryDataSet nestedLoopJoin(DataSet innerLoopDs,  DataSet outerLoopDs, Iterable<FilterItem> filtersIterable){
+    public static InMemoryDataSet nestedLoopJoin(DataSet innerLoopDs, DataSet outerLoopDs,
+            Iterable<FilterItem> filtersIterable) {
 
         List<FilterItem> filters = new ArrayList<>();
-        for(FilterItem fi : filtersIterable){
+        for (FilterItem fi : filtersIterable) {
             filters.add(fi);
         }
         List<Row> innerRows = innerLoopDs.toRows();
 
-
-        List<SelectItem> allItems = new ArrayList<>(Arrays.asList(outerLoopDs.getSelectItems())) ;
+        List<SelectItem> allItems = new ArrayList<>(Arrays.asList(outerLoopDs.getSelectItems()));
         allItems.addAll(Arrays.asList(innerLoopDs.getSelectItems()));
 
-        Set<FilterItem> applicableFilters = applicableFilters(filters,allItems);
+        Set<FilterItem> applicableFilters = applicableFilters(filters, allItems);
 
         DataSetHeader jointHeader = new CachingDataSetHeader(allItems);
 
         List<Row> resultRows = new ArrayList<>();
-        for(Row outerRow: outerLoopDs){
-            for(Row innerRow: innerRows){
+        for (Row outerRow : outerLoopDs) {
+            for (Row innerRow : innerRows) {
 
                 Object[] joinedRowObjects = new Object[outerRow.getValues().length + innerRow.getValues().length];
 
-                System.arraycopy(outerRow.getValues(),0,joinedRowObjects,0,outerRow.getValues().length);
-                System.arraycopy(innerRow.getValues(),0,joinedRowObjects,outerRow.getValues().length,innerRow.getValues().length);
-
-                Row joinedRow =  new DefaultRow(jointHeader,joinedRowObjects);
+                System.arraycopy(outerRow.getValues(), 0, joinedRowObjects, 0, outerRow.getValues().length);
+                System.arraycopy(innerRow.getValues(), 0, joinedRowObjects, outerRow.getValues().length, innerRow
+                        .getValues().length);
 
+                Row joinedRow = new DefaultRow(jointHeader, joinedRowObjects);
 
-                if(applicableFilters.isEmpty()|| applicableFilters.stream().allMatch(fi -> fi.accept(joinedRow))){
+                if (applicableFilters.isEmpty() || applicableFilters.stream().allMatch(fi -> fi.accept(joinedRow))) {
                     resultRows.add(joinedRow);
                 }
             }
         }
 
-        return new InMemoryDataSet(jointHeader,resultRows);
+        return new InMemoryDataSet(jointHeader, resultRows);
     }
 
     /**
      * Filters the FilterItems such that only the FilterItems are returned,
      * which contain SelectItems that are contained in selectItemList
+     * 
      * @param filters
      * @param selectItemList
      * @return
      */
-    private static  Set<FilterItem> applicableFilters(Collection<FilterItem> filters, Collection<SelectItem> selectItemList) {
+    private static Set<FilterItem> applicableFilters(Collection<FilterItem> filters,
+            Collection<SelectItem> selectItemList) {
 
         Set<SelectItem> items = new HashSet<SelectItem>(selectItemList);
 
-        return filters.stream().filter( fi -> {
+        return filters.stream().filter(fi -> {
             Collection<SelectItem> fiSelectItems = new ArrayList<>();
             fiSelectItems.add(fi.getSelectItem());
             Object operand = fi.getOperand();
-            if(operand instanceof SelectItem){
+            if (operand instanceof SelectItem) {
                 fiSelectItems.add((SelectItem) operand);
             }
 
@@ -263,7 +262,6 @@ private static  Set<FilterItem> applicableFilters(Collection<FilterItem> filters
         }).collect(Collectors.toSet());
     }
 
-
     public static DataSet getFiltered(DataSet dataSet, Iterable<FilterItem> filterItems) {
         List<IRowFilter> filters = CollectionUtils.map(filterItems, filterItem -> {
             return filterItem;
diff --git a/core/src/test/java/org/apache/metamodel/MetaModelHelperTest.java b/core/src/test/java/org/apache/metamodel/MetaModelHelperTest.java
index 705c6f167..a84cef1c7 100644
--- a/core/src/test/java/org/apache/metamodel/MetaModelHelperTest.java
+++ b/core/src/test/java/org/apache/metamodel/MetaModelHelperTest.java
@@ -116,14 +116,17 @@ public void testRightJoin() throws Exception {
     public void testSimpleCarthesianProduct() throws Exception {
         DataSet dataSet = MetaModelHelper.getCarthesianProduct(createDataSet1(), createDataSet2());
         List<String> results = new ArrayList<String>();
-        
-        while(dataSet.next()){
-          results.add(dataSet.getRow().toString());
+
+        while (dataSet.next()) {
+            results.add(dataSet.getRow().toString());
         }
         assertEquals(2, dataSet.getSelectItems().length);
         assertEquals(9, results.size());
         assertTrue(results.contains("Row[values=[f, b]]"));
         assertTrue(results.contains("Row[values=[f, a]]"));
+        assertTrue(results.contains("Row[values=[f, r]]"));
+        assertTrue(results.contains("Row[values=[o, b]]"));
+        assertTrue(results.contains("Row[values=[o, a]]"));
         assertTrue(results.contains("Row[values=[o, r]]"));
     }
 
@@ -182,8 +185,8 @@ private DataSet createDataSet1() {
         data1.add(new Object[] { "f" });
         data1.add(new Object[] { "o" });
         data1.add(new Object[] { "o" });
-        DataSet dataSet1 = createDataSet(
-                new SelectItem[] { new SelectItem(new MutableColumn("foo", ColumnType.VARCHAR)) }, data1);
+        DataSet dataSet1 = createDataSet(new SelectItem[] { new SelectItem(new MutableColumn("foo",
+                ColumnType.VARCHAR)) }, data1);
         return dataSet1;
     }
 
@@ -200,8 +203,8 @@ private DataSet createDataSet3() {
         List<Object[]> data3 = new ArrayList<Object[]>();
         data3.add(new Object[] { "w00p", true });
         data3.add(new Object[] { "yippie", false });
-        DataSet dataSet3 = createDataSet(new SelectItem[] { new SelectItem("expression", "e"),
-                new SelectItem("webish?", "w") }, data3);
+        DataSet dataSet3 = createDataSet(new SelectItem[] { new SelectItem("expression", "e"), new SelectItem("webish?",
+                "w") }, data3);
         return dataSet3;
     }
 
@@ -210,9 +213,7 @@ private DataSet createDataSet4() {
         DataSet dataSet4 = createDataSet(new SelectItem[] { new SelectItem("abc", "abc") }, data4);
         return dataSet4;
     }
-    
-    
-    
+
     private int bigDataSetSize = 3000;
 
     /**
@@ -220,42 +221,33 @@ private DataSet createDataSet4() {
      * @return a big dataset, mocking an employee table
      */
     private DataSet createDataSet5() {
-      List<Object[]> data5 = new ArrayList<Object[]>();
-      
-      
-      for(int i = 0; i<bigDataSetSize;i++){
-        data5.add(new Object[]{i,"Person_" + i, bigDataSetSize-(i+1) });
-      }
-      
-      DataSet dataSet5 = createDataSet(
-          new SelectItem[] { 
-              new SelectItem(new MutableColumn("nr", ColumnType.BIGINT)),
-              new SelectItem(new MutableColumn("name", ColumnType.STRING)),
-              new SelectItem(new MutableColumn("dnr", ColumnType.BIGINT))
-          }, 
-          data5);
-      return dataSet5;
-  }
-    
+        List<Object[]> data5 = new ArrayList<Object[]>();
+
+        for (int i = 0; i < bigDataSetSize; i++) {
+            data5.add(new Object[] { i, "Person_" + i, bigDataSetSize - (i + 1) });
+        }
+
+        DataSet dataSet5 = createDataSet(new SelectItem[] { new SelectItem(new MutableColumn("nr", ColumnType.BIGINT)),
+                new SelectItem(new MutableColumn("name", ColumnType.STRING)), new SelectItem(new MutableColumn("dnr",
+                        ColumnType.BIGINT)) }, data5);
+        return dataSet5;
+    }
+
     /**
      * 
      * @return a big dataset, mocking an department table
      */
     private DataSet createDataSet6() {
-      List<Object[]> data6 = new ArrayList<Object[]>();
-
-      for(int i = 0; i<bigDataSetSize;i++){
-        data6.add(new Object[]{i,"Department_" + i });
-      }
-      
-      DataSet dataSet6 = createDataSet(
-          new SelectItem[] { 
-              new SelectItem(new MutableColumn("nr", ColumnType.BIGINT)),
-              new SelectItem(new MutableColumn("name", ColumnType.STRING)),
-          }, 
-          data6);
-      return dataSet6;
-  }
+        List<Object[]> data6 = new ArrayList<Object[]>();
+
+        for (int i = 0; i < bigDataSetSize; i++) {
+            data6.add(new Object[] { i, "Department_" + i });
+        }
+
+        DataSet dataSet6 = createDataSet(new SelectItem[] { new SelectItem(new MutableColumn("nr", ColumnType.BIGINT)),
+                new SelectItem(new MutableColumn("name", ColumnType.STRING)), }, data6);
+        return dataSet6;
+    }
 
     public void testGetTables() throws Exception {
         MutableTable table1 = new MutableTable("table1");
@@ -365,23 +357,22 @@ public void testLeftJoinNoRowsOrSingleRow() throws Exception {
         assertEquals("Row[values=[1, 2, null]]", joinedDs.getRow().toString());
         assertFalse(joinedDs.next());
     }
-    
-    
-    public void testCarthesianProductScalability(){
-      
-      DataSet employees = createDataSet5();
-      DataSet departmens = createDataSet6();
-      
-      FilterItem fi = new FilterItem(employees.getSelectItems()[2], OperatorType.EQUALS_TO,departmens.getSelectItems()[0]);
-      
-      DataSet joined =  MetaModelHelper.getCarthesianProduct(new DataSet[]{employees,departmens}, fi);
-      int count = 0; 
-      while(joined.next()){
-        count++;
-      }
-      
-      assertTrue(count == bigDataSetSize);
-      
-      
+
+    public void testCarthesianProductScalability() {
+
+        DataSet employees = createDataSet5();
+        DataSet departmens = createDataSet6();
+
+        FilterItem fi = new FilterItem(employees.getSelectItems()[2], OperatorType.EQUALS_TO, departmens
+                .getSelectItems()[0]);
+
+        DataSet joined = MetaModelHelper.getCarthesianProduct(new DataSet[] { employees, departmens }, fi);
+        int count = 0;
+        while (joined.next()) {
+            count++;
+        }
+
+        assertTrue(count == bigDataSetSize);
+
     }
 }
diff --git a/jdbc/src/test/java/org/apache/metamodel/jdbc/MultiJDBCDataSetTest.java b/jdbc/src/test/java/org/apache/metamodel/jdbc/MultiJDBCDataSetTest.java
index d91036211..0b60f9536 100644
--- a/jdbc/src/test/java/org/apache/metamodel/jdbc/MultiJDBCDataSetTest.java
+++ b/jdbc/src/test/java/org/apache/metamodel/jdbc/MultiJDBCDataSetTest.java
@@ -36,11 +36,11 @@
 import java.util.concurrent.TimeUnit;
 
 /**
- * A test case using two simple h2 in memory databases for executing single query over both databases.
+ * A test case using two simple h2 in memory databases for executing single
+ * query over both databases.
  */
 public class MultiJDBCDataSetTest {
 
-
     public static final String DRIVER_CLASS = "org.h2.Driver";
     public static final String EMP_URL_MEMORY_DATABASE = "jdbc:h2:mem:emp";
     public static final String DEP_URL_MEMORY_DATABASE = "jdbc:h2:mem:dep";
@@ -53,109 +53,80 @@ public class MultiJDBCDataSetTest {
 
     private int employeeSize = 10000;
     private int departmentSize = 1000;
-    int employeesPerDepartment =  employeeSize/ departmentSize;
-
+    int employeesPerDepartment = employeeSize / departmentSize;
 
     private static final Logger logger = LoggerFactory.getLogger(MultiJDBCDataSetTest.class);
 
-
     @Before
     public void setup() throws Exception {
         Class.forName(DRIVER_CLASS);
         emp_conn = DriverManager.getConnection(EMP_URL_MEMORY_DATABASE);
-        dep_conn =  DriverManager.getConnection(DEP_URL_MEMORY_DATABASE);
-
+        dep_conn = DriverManager.getConnection(DEP_URL_MEMORY_DATABASE);
 
         emp_dcon = new JdbcDataContext(emp_conn);
         dep_dcon = new JdbcDataContext(dep_conn);
 
+        emp_dcon.executeUpdate(new CreateTable(emp_dcon.getDefaultSchema(), "employee").withColumn("id").ofType(
+                ColumnType.INTEGER).asPrimaryKey().withColumn("name").ofType(ColumnType.VARCHAR).ofSize(200).withColumn(
+                        "dep_id").ofType(ColumnType.INTEGER));
 
-
-
-        emp_dcon.executeUpdate(new CreateTable(emp_dcon.getDefaultSchema(),"employee")
-                .withColumn("id").ofType(ColumnType.INTEGER).asPrimaryKey()
-                .withColumn("name").ofType(ColumnType.VARCHAR).ofSize(200)
-                .withColumn("dep_id").ofType(ColumnType.INTEGER));
-
-
-        for(int i = 0;i<employeeSize;i++){
-            emp_dcon.executeUpdate(new InsertInto(emp_dcon.getDefaultSchema().getTableByName("employee"))
-                    .value("id",i)
-                    .value("name","emp" + i)
-                    .value("dep_id",i% departmentSize));
+        for (int i = 0; i < employeeSize; i++) {
+            emp_dcon.executeUpdate(new InsertInto(emp_dcon.getDefaultSchema().getTableByName("employee")).value("id", i)
+                    .value("name", "emp" + i).value("dep_id", i % departmentSize));
         }
 
+        dep_dcon.executeUpdate(new CreateTable(dep_dcon.getDefaultSchema(), "department").withColumn("id").ofType(
+                ColumnType.INTEGER).asPrimaryKey().withColumn("name").ofType(ColumnType.VARCHAR).ofSize(200));
 
-        dep_dcon.executeUpdate(new CreateTable(dep_dcon.getDefaultSchema(),"department")
-                .withColumn("id").ofType(ColumnType.INTEGER).asPrimaryKey()
-                .withColumn("name").ofType(ColumnType.VARCHAR).ofSize(200));
-
-
-        for(int i = 0; i< departmentSize; i++){
-            dep_dcon.executeUpdate(new InsertInto(dep_dcon.getDefaultSchema().getTableByName("department"))
-                    .value("id",i)
-                    .value("name","dep" + i));
+        for (int i = 0; i < departmentSize; i++) {
+            dep_dcon.executeUpdate(new InsertInto(dep_dcon.getDefaultSchema().getTableByName("department")).value("id",
+                    i).value("name", "dep" + i));
         }
 
     }
 
-
     @After
-    public void tearDown(){
+    public void tearDown() {
         dep_dcon.executeUpdate(new DropTable("department"));
         emp_dcon.executeUpdate(new DropTable("employee"));
     }
 
-
-
     @Test
-    public void testJoin(){
+    public void testJoin() {
         Stopwatch duration = Stopwatch.createStarted();
-        CompositeDataContext compDcon = new CompositeDataContext(this.emp_dcon,this.dep_dcon );
-
-        DataSet ds = compDcon.query()
-                .from("employee")
-                .innerJoin("department")
-                .on("dep_id","id")
-                .selectAll()
-                .execute();
+        CompositeDataContext compDcon = new CompositeDataContext(this.emp_dcon, this.dep_dcon);
+
+        DataSet ds = compDcon.query().from("employee").innerJoin("department").on("dep_id", "id").selectAll().execute();
         int rowCount = 0;
-        while(ds.next()){
+        while (ds.next()) {
             Row row = ds.getRow();
+            Assert.assertNotNull(row);
             rowCount++;
         }
         duration.stop();
         logger.info("Test duration was {} ms", duration.elapsed(TimeUnit.MILLISECONDS));
 
-        Assert.assertEquals(employeeSize,rowCount);
+        Assert.assertEquals(employeeSize, rowCount);
 
     }
 
     @Test
-    public void testSelectiveJoin(){
+    public void testSelectiveJoin() {
         Stopwatch duration = Stopwatch.createStarted();
-        CompositeDataContext compDcon = new CompositeDataContext(this.emp_dcon,this.dep_dcon );
-
-        DataSet ds = compDcon.query()
-                .from("employee")
-                .innerJoin("department")
-                .on("dep_id","id")
-                .selectAll()
-                .where(compDcon.getTableByQualifiedLabel("department").getColumnByName("id")).eq(1)
-                .execute();
+        CompositeDataContext compDcon = new CompositeDataContext(this.emp_dcon, this.dep_dcon);
+
+        DataSet ds = compDcon.query().from("employee").innerJoin("department").on("dep_id", "id").selectAll().where(
+                compDcon.getTableByQualifiedLabel("department").getColumnByName("id")).eq(1).execute();
         int rowCount = 0;
-        while(ds.next()){
+        while (ds.next()) {
             Row row = ds.getRow();
+            Assert.assertNotNull(row);
             rowCount++;
         }
         duration.stop();
         logger.info("Test duration was {} ms", duration.elapsed(TimeUnit.MILLISECONDS));
 
-        Assert.assertEquals(employeesPerDepartment,rowCount);
-
+        Assert.assertEquals(employeesPerDepartment, rowCount);
     }
 
-
-
-
 }