--- a/src/goodjava/io/BufferedInputStream.java	Sun May 03 00:12:15 2020 -0600
+++ b/src/goodjava/io/BufferedInputStream.java	Sun May 03 11:51:31 2020 -0600
@@ -6,7 +6,6 @@
 package goodjava.io;
 
 import java.io.InputStream;
-import java.io.FilterInputStream;
 import java.io.IOException;
 
 /**
@@ -22,7 +21,7 @@
  * @author  Arthur van Hoff
  * @since   JDK1.0
  */
-public final class BufferedInputStream extends FilterInputStream {
+public final class BufferedInputStream extends NoMarkInputStream {
 	private final byte buf[];
 
 	/**
@@ -83,14 +82,13 @@
 
 	/**
 	 * Fills the buffer with more data.
-	 * Assumes that it is being called by a synchronized method.
 	 * This method also assumes that all data has already been read in,
 	 * hence pos > count.
 	 */
 	private void fill() throws IOException {
 		pos = 0;
 		count = 0;
-		int n = super.read(buf, 0, buf.length);
+		int n = in.read(buf, 0, buf.length);
 		if (n > 0)
 			count = n;
 	}
@@ -107,7 +105,7 @@
 	 *                          or an I/O error occurs.
 	 * @see        java.io.FilterInputStream#in
 	 */
-	public synchronized int read() throws IOException {
+	public int read() throws IOException {
 		if (pos >= count) {
 			fill();
 			if (pos >= count)
@@ -133,7 +131,7 @@
 			off += cnt;
 		}
 		if (len >= buf.length) {
-			return cnt + Math.max( 0, super.read(b, off, len) );
+			return cnt + Math.max( 0, in.read(b, off, len) );
 		}
 		fill();
 		if (count <= 0)
@@ -143,7 +141,7 @@
 		return cnt + len;
 	}
 
-	public synchronized int read(byte[] b, int off, int len) throws IOException {
+	public int read(byte[] b, int off, int len) throws IOException {
 		if( len == 0 )
 			return 0;
 		int n = read1(b,off,len);
@@ -159,7 +157,7 @@
 	 *                          invoking its {@link #close()} method, or an
 	 *                          I/O error occurs.
 	 */
-	public synchronized long skip(long n) throws IOException {
+	public long skip(long n) throws IOException {
 		if( n <= 0 )
 			return 0;
 		long skipped = 0;
@@ -171,7 +169,7 @@
 			if( n == 0 )
 				return skipped;
 		}
-		return skipped + super.skip(n);
+		return skipped + in.skip(n);
 	}
 
 	/**
@@ -191,22 +189,12 @@
 	 *                          invoking its {@link #close()} method,
 	 *                          or an I/O error occurs.
 	 */
-	public synchronized int available() throws IOException {
+	public int available() throws IOException {
 		int n = count - pos;
-		int avail = super.available();
+		int avail = in.available();
 		return n > (Integer.MAX_VALUE - avail)
 					? Integer.MAX_VALUE
 					: n + avail;
 	}
 
-	public void mark(int readlimit) {}
-
-	public void reset() throws IOException {
-		throw new IOException("mark/reset not supported");
-	}
-
-	public boolean markSupported() {
-		return false;
-	}
-
 }