diff a/test/lib/org/openjdk/asmtools/jcoder/ByteBuffer.java b/test/lib/org/openjdk/asmtools/jcoder/ByteBuffer.java
--- /dev/null
+++ b/test/lib/org/openjdk/asmtools/jcoder/ByteBuffer.java
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2009, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.openjdk.asmtools.jcoder;
+
+/**
+ * Compiles just 1 source file
+ */
+class ByteBuffer extends java.io.OutputStream {
+
+    String myname;
+    /**
+     * The buffer where elements are stored.
+     */
+    byte data[];
+    /**
+     * The number of elements in the buffer.
+     */
+    int length;
+    /**
+     * The size of the increment. If it is 0 the size of the the buffer is doubled
+     * everytime it needs to grow.
+     */
+    protected int capacityIncrement;
+
+    /**
+     * Constructs an empty vector with the specified storage capacity and the specified
+     * capacityIncrement.
+     *
+     * @param initialCapacity the initial storage capacity of the vector
+     * @param capacityIncrement how much to increase the element's size by.
+     */
+    public ByteBuffer(int initialCapacity, int capacityIncrement) {
+//      super();
+        this.data = new byte[initialCapacity];
+        this.capacityIncrement = capacityIncrement;
+    }
+
+    /**
+     * Constructs an empty vector with the specified storage capacity.
+     *
+     * @param initialCapacity the initial storage capacity of the vector
+     */
+    public ByteBuffer(int initialCapacity) {
+        this(initialCapacity, 0);
+    }
+
+    /**
+     * Constructs an empty vector.
+     */
+    public ByteBuffer() {
+        this(30);
+    }
+
+    /**
+     * Constructs a full vector.
+     */
+    public ByteBuffer(byte data[], int capacityIncrement) {
+        this.length = data.length;
+        this.data = data;
+        this.capacityIncrement = capacityIncrement;
+    }
+
+    /**
+     * Constructs a full vector.
+     */
+    public ByteBuffer(byte data[]) {
+        this(data, 0);
+    }
+
+    /**
+     * Returns the number of elements in the vector. Note that this is not the same as the
+     * vector's capacity.
+     */
+    public final int size() {
+        return length;
+    }
+
+    /**
+     * Ensures that the vector has at least the specified capacity.
+     *
+     * @param minCapacity the desired minimum capacity
+     */
+    public final synchronized void ensureCapacity(int minCapacity) {
+        int oldCapacity = data.length;
+        if (minCapacity <= oldCapacity) {
+            return;
+        }
+        byte oldData[] = data;
+        int newCapacity = (capacityIncrement > 0) ? (oldCapacity + capacityIncrement) : (oldCapacity * 2);
+        if (newCapacity < minCapacity) {
+            newCapacity = minCapacity;
+        }
+        data = new byte[newCapacity];
+        System.arraycopy(oldData, 0, data, 0, length);
+    }
+
+    /*======================================*/
+    public void write(int val) {
+        ensureCapacity(length + 1);
+        data[length++] = (byte) val;
+    }
+
+    public void writeAt(int index, long val, int width) {
+        for (int i = 0; i < width; i++) {
+            data[index + i] = (byte) (val >> (width - 1 - i) * 8);
+        }
+    }
+
+    public void append(long val, int width) {
+        ensureCapacity(length + width);
+        writeAt(length, val, width);
+        length += width;
+    }
+
+    /*======================================================*/
+} // end ByteBuffer
+
