diff --git a/src/runtime/java/jpgf.c b/src/runtime/java/jpgf.c
index bca7a64e0..9b09068d5 100644
--- a/src/runtime/java/jpgf.c
+++ b/src/runtime/java/jpgf.c
@@ -1388,6 +1388,13 @@ Java_org_grammaticalframework_pgf_Expr_equals(JNIEnv* env, jobject self, jobject
 		return JNI_FALSE;
 }
 
+JNIEXPORT jint JNICALL
+Java_org_grammaticalframework_pgf_Expr_hashCode(JNIEnv* env, jobject self)
+{
+	PgfExpr e = gu_variant_from_ptr(l2p(get_ref(env, self)));
+	return pgf_expr_hash(0, e);
+}
+
 JNIEXPORT jstring JNICALL
 Java_org_grammaticalframework_pgf_Type_getCategory(JNIEnv* env, jobject self)
 {
diff --git a/src/runtime/java/org/grammaticalframework/pgf/Expr.java b/src/runtime/java/org/grammaticalframework/pgf/Expr.java
index cdc62d1d1..08e75ea04 100644
--- a/src/runtime/java/org/grammaticalframework/pgf/Expr.java
+++ b/src/runtime/java/org/grammaticalframework/pgf/Expr.java
@@ -102,6 +102,8 @@ public class Expr implements Serializable {
 		 * @return True if the expressions are equal. */
 		public native boolean equals(Expr e);
 
+		public native int hashCode();
+
 		private static native String showExpr(long ref);
 
 		private static native long initStringLit(String s, long pool);