diff --git a/runtime/Java/src/org/antlr/v4/runtime/misc/IntSet.java b/runtime/Java/src/org/antlr/v4/runtime/misc/IntSet.java
index d4d499ff2..9edd1c3ea 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/misc/IntSet.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/misc/IntSet.java
@@ -128,16 +128,6 @@ public interface IntSet {
 	@Override
 	boolean equals(Object obj);
 
-	/**
-	 * Returns the single value contained in the set, if {@link #size} is 1;
-	 * otherwise, result is undefined.  Check {@link #isNil()} before using
-	 * this function.
-	 *
-	 * @return the single value contained in the set, if {@link #size} is 1;
-	 * otherwise, result is undefined.
-	 */
-	int getSingleElement();
-
 	/**
 	 * Returns {@code true} if the set contains the specified element.
 	 *
diff --git a/runtime/Java/src/org/antlr/v4/runtime/misc/IntervalSet.java b/runtime/Java/src/org/antlr/v4/runtime/misc/IntervalSet.java
index 8ed76c6d7..57ccba055 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/misc/IntervalSet.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/misc/IntervalSet.java
@@ -416,28 +416,15 @@ public class IntervalSet implements IntSet {
         return intervals==null || intervals.isEmpty();
     }
 
-    /** {@inheritDoc} */
-    @Override
-    public int getSingleElement() {
-        if ( intervals!=null && intervals.size()==1 ) {
-            Interval I = intervals.get(0);
-            if ( I.a == I.b ) {
-                return I.a;
-            }
-        }
-        return Token.INVALID_TYPE;
-    }
-
 	/**
 	 * Returns the maximum value contained in the set if not isNil().
-	 * Otherwise, result is undefined.
 	 *
-	 * @return the maximum value contained in the set. If the set is empty,
-	 * result is undefined.
+	 * @return the maximum value contained in the set.
+	 * @throws RuntimeException if set is empty
 	 */
 	public int getMaxElement() {
 		if ( isNil() ) {
-			return Token.INVALID_TYPE;
+			throw new RuntimeException("set is empty");
 		}
 		Interval last = intervals.get(intervals.size()-1);
 		return last.b;
@@ -445,14 +432,13 @@ public class IntervalSet implements IntSet {
 
 	/**
 	 * Returns the minimum value contained in the set if not isNil().
-	 * Otherwise, result is undefined.
 	 *
-	 * @return the minimum value contained in the set. If the set is empty,
-	 * result is undefined.
+	 * @return the minimum value contained in the set.
+	 * @throws RuntimeException if set is empty
 	 */
 	public int getMinElement() {
 		if ( isNil() ) {
-			return Token.INVALID_TYPE;
+			throw new RuntimeException("set is empty");
 		}
 
 		return intervals.get(0).a;