diff --git a/src/runtime/java/jpgf.c b/src/runtime/java/jpgf.c
index 3f3217ed1..41761a5a0 100644
--- a/src/runtime/java/jpgf.c
+++ b/src/runtime/java/jpgf.c
@@ -51,16 +51,10 @@ j2gu_string(JNIEnv *env, jstring s, GuPool* pool) {
 	return gu_str_string(str, pool);
 }
 
-static PgfPGF*
-get_pgf(JNIEnv *env, jobject self) {
-	jfieldID grId = (*env)->GetFieldID(env, (*env)->GetObjectClass(env, self), "gr", "J");
-	return (PgfPGF*) (*env)->GetLongField(env, self, grId);
-}
-
-static PgfPGF*
-get_concr(JNIEnv *env, jobject self) {
-	jfieldID concrId = (*env)->GetFieldID(env, (*env)->GetObjectClass(env, self), "concr", "J");
-	return (PgfPGF*) (*env)->GetLongField(env, self, concrId);
+static void*
+get_ref(JNIEnv *env, jobject self) {
+	jfieldID refId = (*env)->GetFieldID(env, (*env)->GetObjectClass(env, self), "ref", "J");
+	return (void*) (*env)->GetLongField(env, self, refId);
 }
 
 static void
@@ -123,7 +117,7 @@ Java_org_grammaticalframework_pgf_PGF_readPGF(JNIEnv *env, jclass cls, jstring s
 JNIEXPORT jstring JNICALL 
 Java_org_grammaticalframework_pgf_PGF_getAbstractName(JNIEnv* env, jobject self)
 {
-	return gu2j_string(env, pgf_abstract_name(get_pgf(env, self)));
+	return gu2j_string(env, pgf_abstract_name(get_ref(env, self)));
 }
 
 JNIEXPORT void JNICALL 
@@ -171,7 +165,7 @@ Java_org_grammaticalframework_pgf_PGF_getLanguages(JNIEnv* env, jobject self)
 	if (!languages)
 		return NULL;
 
-	PgfPGF* pgf = get_pgf(env, self);
+	PgfPGF* pgf = get_ref(env, self);
 
 	GuPool* tmp_pool = gu_local_pool();
 
@@ -193,7 +187,7 @@ Java_org_grammaticalframework_pgf_PGF_getLanguages(JNIEnv* env, jobject self)
 JNIEXPORT jstring JNICALL 
 Java_org_grammaticalframework_pgf_Concr_getName(JNIEnv* env, jobject self)
 {
-	return gu2j_string(env, pgf_concrete_name(get_concr(env, self)));
+	return gu2j_string(env, pgf_concrete_name(get_ref(env, self)));
 }
 
 JNIEXPORT jobject JNICALL 
@@ -210,7 +204,7 @@ Java_org_grammaticalframework_pgf_Parser_parse
 	PgfLexer *lexer = pgf_new_simple_lexer(rdr, pool);
 
 	GuEnum* res =
-		pgf_parse(get_concr(env, concr), startCat, lexer, pool, out_pool);
+		pgf_parse(get_ref(env, concr), startCat, lexer, pool, out_pool);
 
 	if (res == NULL) {
 		PgfToken tok =
@@ -256,7 +250,7 @@ Java_org_grammaticalframework_pgf_Pool_free(JNIEnv* env, jobject self, jlong ref
 	gu_pool_free((GuPool*) ref);
 }
 
-JNIEXPORT jstring JNICALL 
+JNIEXPORT jstring JNICALL
 Java_org_grammaticalframework_pgf_Expr_showExpr(JNIEnv* env, jclass clazz, jlong ref)
 {
 	GuPool* tmp_pool = gu_local_pool();
diff --git a/src/runtime/java/org/grammaticalframework/pgf/Concr.java b/src/runtime/java/org/grammaticalframework/pgf/Concr.java
index 0f91539a0..f7ec88b60 100644
--- a/src/runtime/java/org/grammaticalframework/pgf/Concr.java
+++ b/src/runtime/java/org/grammaticalframework/pgf/Concr.java
@@ -14,10 +14,10 @@ public class Concr {
 	// private stuff
 	
 	private PGF gr;
-	public long concr;
+	public long ref;
 
-	private Concr(PGF gr, long concr) {
-		this.gr    = gr;
-		this.concr = concr;
+	private Concr(PGF gr, long ref) {
+		this.gr  = gr;
+		this.ref = ref;
 	}
 }
diff --git a/src/runtime/java/org/grammaticalframework/pgf/ExprIterator.java b/src/runtime/java/org/grammaticalframework/pgf/ExprIterator.java
index be90d07c5..1ab9cae26 100644
--- a/src/runtime/java/org/grammaticalframework/pgf/ExprIterator.java
+++ b/src/runtime/java/org/grammaticalframework/pgf/ExprIterator.java
@@ -3,20 +3,22 @@ package org.grammaticalframework.pgf;
 import java.util.*;
 
 class ExprIterator implements Iterator<ExprProb> {
+	private Concr concr;
 	private Pool pool, out_pool;
-	private long enumRef;
+	private long ref;
 	private ExprProb ep;
 	private boolean fetched;
 
-	public ExprIterator(long pool, long out_pool, long enumRef) {
-		this.pool = new Pool(pool);
+	public ExprIterator(Concr concr, long pool, long out_pool, long ref) {
+		this.concr    = concr;
+		this.pool     = new Pool(pool);
 		this.out_pool = new Pool(out_pool);
-		this.enumRef = enumRef;
-		this.ep = null;
-		this.fetched = false;
+		this.ref      = ref;
+		this.ep       = null;
+		this.fetched  = false;
 	}
 
-	private native ExprProb fetchExprProb(long enumRef, Pool out_pool);
+	private native ExprProb fetchExprProb(long ref, Pool out_pool);
 
 	private void fetch() {
 		if (!fetched) {
diff --git a/src/runtime/java/org/grammaticalframework/pgf/PGF.java b/src/runtime/java/org/grammaticalframework/pgf/PGF.java
index 35ff8d044..467065d00 100644
--- a/src/runtime/java/org/grammaticalframework/pgf/PGF.java
+++ b/src/runtime/java/org/grammaticalframework/pgf/PGF.java
@@ -30,18 +30,18 @@ public class PGF {
 	private static native void free(long pool);
 
 	private long pool;
-	private long gr;
+	private long ref;
 
-	private PGF(long pool, long gr) {
+	private PGF(long pool, long ref) {
 		this.pool = pool;
-		this.gr   = gr;
+		this.ref  = ref;
 	}
 
 	protected void finalize () throws Throwable {
 		if (pool != 0) {
 			free(pool);
 			pool = 0;
-			gr = 0;
+			ref = 0;
 		}
 	}