Optimize exists queries

querydsl-jpa/src/main/java/com/querydsl/jpa/EclipseLinkTemplates.java

@@ -95,10 +95,4 @@ public boolean isPathInEntitiesSupported() {
         return false;
     }
 
-    @Override
-    public boolean isSelect1Supported() {
-        return true;
-    }
-
-
 }

querydsl-jpa/src/main/java/com/querydsl/jpa/HQLTemplates.java

@@ -116,12 +116,6 @@ public String getExistsProjection() {
         return "1";
     }
 
-    @Override
-    public boolean isSelect1Supported() {
-        // TODO return true, when JPQLTemplates becomes standard
-        return false;
-    }
-
     @Override
     public boolean isEnumInPathSupported() {
         // related : http://opensource.atlassian.com/projects/hibernate/browse/HHH-5159

querydsl-jpa/src/main/java/com/querydsl/jpa/JPAQueryBase.java

@@ -64,12 +64,7 @@ protected void reset() {
 
     @Override
     public boolean exists() {
-        if (templates.isSelect1Supported()) {
-            return singleResult(NumberTemplate.ONE) != null;
-        } else {            
-            EntityPath<?> entityPath = (EntityPath<?>) queryMixin.getMetadata().getJoins().get(0).getTarget();
-            return !limit(1).list(entityPath).isEmpty();
-        }                
+        return singleResult(NumberTemplate.ONE) != null;
     }
 
     public Q fetch() {

querydsl-jpa/src/main/java/com/querydsl/jpa/JPQLTemplates.java

@@ -158,10 +158,6 @@ public boolean isPathInEntitiesSupported() {
         return true;
     }
 
-    public boolean isSelect1Supported() {
-        return false;
-    }
-
     @Nullable
     public String getExistsProjection() {
         return null;

querydsl-jpa/src/test/java/com/querydsl/jpa/AbstractJPATest.java

@@ -621,6 +621,7 @@ public void Enum_StartsWith() {
     @Test
     public void Exists() {
         assertTrue(query().from(cat).where(cat.kittens.any().name.eq("Ruth123")).exists());
+        assertFalse(query().from(cat).where(cat.kittens.any().name.eq("Ruth321")).exists());
     }
 
     @Test