--- old/src/com/sun/org/apache/bcel/internal/util/InstructionFinder.java	2020-08-13 14:42:43.754363195 +0100
+++ new/src/com/sun/org/apache/bcel/internal/util/InstructionFinder.java	2020-08-13 14:42:43.646362076 +0100
@@ -4,64 +4,29 @@
  */
 package com.sun.org.apache.bcel.internal.util;
 
-/* ====================================================================
- * The Apache Software License, Version 1.1
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
  *
- * Copyright (c) 2001 The Apache Software Foundation.  All rights
- * reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * 3. The end-user documentation included with the redistribution,
- *    if any, must include the following acknowledgment:
- *       "This product includes software developed by the
- *        Apache Software Foundation (http://www.apache.org/)."
- *    Alternately, this acknowledgment may appear in the software itself,
- *    if and wherever such third-party acknowledgments normally appear.
- *
- * 4. The names "Apache" and "Apache Software Foundation" and
- *    "Apache BCEL" must not be used to endorse or promote products
- *    derived from this software without prior written permission. For
- *    written permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache",
- *    "Apache BCEL", nor may "Apache" appear in their name, without
- *    prior written permission of the Apache Software Foundation.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation.  For more
- * information on the Apache Software Foundation, please see
- * <http://www.apache.org/>.
  */
 
-import java.util.*;
 import com.sun.org.apache.bcel.internal.Constants;
 import com.sun.org.apache.bcel.internal.generic.*;
-import com.sun.org.apache.regexp.internal.*;
+import java.util.*;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * InstructionFinder is a tool to search for given instructions patterns,
@@ -231,28 +196,22 @@
     if(start == -1)
       throw new ClassGenException("Instruction handle " + from +
                                   " not found in instruction list.");
-    try {
-      RE regex = new RE(search);
-      ArrayList matches = new ArrayList();
-
-      while(start < il_string.length() && regex.match(il_string, start)) {
-        int startExpr = regex.getParenStart(0);
-        int endExpr   = regex.getParenEnd(0);
-        int lenExpr   = regex.getParenLength(0);
-
-        InstructionHandle[] match = getMatch(startExpr, lenExpr);
-
-        if((constraint == null) || constraint.checkCode(match))
-          matches.add(match);
-        start = endExpr;
-      }
 
-      return matches.iterator();
-    } catch(RESyntaxException e) {
-      System.err.println(e);
+    Pattern regex = Pattern.compile(search);
+    List<InstructionHandle[]> matches = new ArrayList<>();
+    Matcher matcher = regex.matcher(il_string);
+    while(start < il_string.length() && matcher.find(start)) {
+      int startExpr = matcher.start();
+      int endExpr   = matcher.end();
+      int lenExpr   = endExpr - startExpr;
+      InstructionHandle[] match = getMatch(startExpr, lenExpr);
+
+      if((constraint == null) || constraint.checkCode(match))
+        matches.add(match);
+      start = endExpr;
     }
 
-    return null;
+    return matches.iterator();
   }
 
   /**