diff --git a/classpath/java/io/BufferedReader.java b/classpath/java/io/BufferedReader.java
new file mode 100644
index 0000000000..5bd25e9051
--- /dev/null
+++ b/classpath/java/io/BufferedReader.java
@@ -0,0 +1,57 @@
+package java.io;
+
+public class BufferedReader extends Reader {
+  private final Reader in;
+  private final char[] buffer;
+  private int position;
+  private int limit;
+
+  public BufferedReader(Reader in, int bufferSize) {
+    this.in = in;
+    this.buffer = new char[bufferSize];
+  }
+
+  protected BufferedReader(Reader in) {
+    this(in, 32);
+  }
+  
+  private void fill() throws IOException {
+    position = 0;
+    limit = in.read(buffer);
+  }
+
+  public int read(char[] b, int offset, int length) throws IOException {
+    int count = 0;
+
+    if (position < limit) {
+      int remaining = limit - position;
+      if (remaining > length) {
+        remaining = length;
+      }
+
+      System.arraycopy(buffer, position, b, offset, remaining);
+
+      count += remaining;
+      position += remaining;
+      offset += remaining;
+      length -= remaining;
+    }
+
+    if (length > 0) {
+      int c = in.read(b, offset, length);
+      if (c == -1) {
+        if (count == 0) {
+          count = -1;
+        }
+      } else {
+        count += c;
+      }
+    }
+
+    return count;
+  }
+
+  public void close() throws IOException {
+    in.close();
+  }
+}
diff --git a/classpath/java/io/BufferedWriter.java b/classpath/java/io/BufferedWriter.java
new file mode 100644
index 0000000000..4f246216e5
--- /dev/null
+++ b/classpath/java/io/BufferedWriter.java
@@ -0,0 +1,43 @@
+package java.io;
+
+public class BufferedWriter extends Writer {
+  private final Writer out;
+  private final char[] buffer;
+  private int position;
+
+  public BufferedWriter(Writer out, int size) {
+    this.out = out;
+    this.buffer = new char[size];
+  }
+  
+  public BufferedWriter(Writer out) {
+    this(out, 4096);
+  }
+  
+  private void drain() throws IOException {
+    if (position > 0) {
+      out.write(buffer, 0, position);
+      position = 0;
+    }
+  }
+
+  public void write(char[] b, int offset, int length) throws IOException {
+    if (length > buffer.length - position) {
+      drain();
+      out.write(b, offset, length);      
+    } else {
+      System.arraycopy(b, offset, buffer, position, length);
+      position += length;
+    }
+  }
+
+  public void flush() throws IOException {
+    drain();
+    out.flush();
+  }
+
+  public void close() throws IOException {
+    flush();
+    out.close();
+  }
+}
diff --git a/classpath/java/io/FileReader.java b/classpath/java/io/FileReader.java
new file mode 100644
index 0000000000..3771453805
--- /dev/null
+++ b/classpath/java/io/FileReader.java
@@ -0,0 +1,29 @@
+package java.io;
+
+public class FileReader extends Reader {
+  private final Reader in;
+
+  public FileReader(FileInputStream in) {
+    this.in = new InputStreamReader(in);
+  }
+  
+  public FileReader(FileDescriptor fd) {
+    this(new FileInputStream(fd));
+  }
+
+  public FileReader(String path) throws IOException {
+    this(new FileInputStream(path));
+  }
+
+  public FileReader(File file) throws IOException {
+    this(new FileInputStream(file));
+  }
+
+  public int read(char[] b, int offset, int length) throws IOException {
+    return in.read(b, offset, length);
+  }
+
+  public void close() throws IOException {
+    in.close();
+  }
+}
diff --git a/classpath/java/io/FileWriter.java b/classpath/java/io/FileWriter.java
new file mode 100644
index 0000000000..ab1978762a
--- /dev/null
+++ b/classpath/java/io/FileWriter.java
@@ -0,0 +1,33 @@
+package java.io;
+
+public class FileWriter extends Writer {
+  private final Writer out;
+
+  private FileWriter(FileOutputStream out) {
+    this.out = new OutputStreamWriter(out);
+  }
+
+  public FileWriter(FileDescriptor fd) {
+    this(new FileOutputStream(fd));
+  }
+
+  public FileWriter(String path) throws IOException {
+    this(new FileOutputStream(path));
+  }
+
+  public FileWriter(File file) throws IOException {
+    this(new FileOutputStream(file));
+  }
+  
+  public void write(char[] b, int offset, int length) throws IOException {
+    out.write(b, offset, length);
+  }
+
+  public void flush() throws IOException {
+    out.flush();
+  }
+
+  public void close() throws IOException {
+    out.close();
+  }
+}
diff --git a/classpath/java/io/InputStreamReader.java b/classpath/java/io/InputStreamReader.java
new file mode 100644
index 0000000000..a318289179
--- /dev/null
+++ b/classpath/java/io/InputStreamReader.java
@@ -0,0 +1,22 @@
+package java.io;
+
+public class InputStreamReader extends Reader {
+  private final InputStream in;
+
+  public InputStreamReader(InputStream in) {
+    this.in = in;
+  }
+  
+  public int read(char[] b, int offset, int length) throws IOException {
+    byte[] buffer = new byte[length];
+    int c = in.read(buffer);
+    for (int i = 0; i < c; ++i) {
+      b[i + offset] = (char) buffer[i];
+    }
+    return c;
+  }
+
+  public void close() throws IOException {
+    in.close();
+  }
+}
diff --git a/classpath/java/io/LineNumberReader.java b/classpath/java/io/LineNumberReader.java
new file mode 100644
index 0000000000..b3876f37aa
--- /dev/null
+++ b/classpath/java/io/LineNumberReader.java
@@ -0,0 +1,31 @@
+package java.io;
+
+public class LineNumberReader extends BufferedReader {
+  private int line;
+
+  public LineNumberReader(Reader in, int bufferSize) {
+    super(in, bufferSize);
+  }
+
+  protected LineNumberReader(Reader in) {
+    super(in);
+  }
+
+  public int getLineNumber() {
+    return line;
+  }
+
+  public void setLineNumber(int v) {
+    line = v;
+  }
+  
+  public int read(char[] b, int offset, int length) throws IOException {
+    int c = super.read(b, offset, length);
+    for (int i = 0; i < c; ++i) {
+      if (b[i] == '\n') {
+        ++ line;
+      }
+    }
+    return c;
+  }
+}
diff --git a/classpath/java/io/ObjectInputStream.java b/classpath/java/io/ObjectInputStream.java
new file mode 100644
index 0000000000..d0adaf0ad5
--- /dev/null
+++ b/classpath/java/io/ObjectInputStream.java
@@ -0,0 +1,21 @@
+package java.io;
+
+public class ObjectInputStream extends InputStream {
+  private final InputStream in;
+
+  public ObjectInputStream(InputStream in) {
+    this.in = in;
+  }
+
+  public int read() throws IOException {
+    return in.read();
+  }
+
+  public int read(byte[] b, int offset, int length) throws IOException {
+    return in.read(b, offset, length);
+  }
+
+  public void close() throws IOException {
+    in.close();
+  }
+}
diff --git a/classpath/java/io/ObjectOutputStream.java b/classpath/java/io/ObjectOutputStream.java
new file mode 100644
index 0000000000..9a57d10bcd
--- /dev/null
+++ b/classpath/java/io/ObjectOutputStream.java
@@ -0,0 +1,26 @@
+package java.io;
+
+public class ObjectOutputStream extends OutputStream {
+  private final OutputStream out;
+
+  public ObjectOutputStream(OutputStream out) {
+    this.out = out;
+  }
+  
+  public void write(int c) throws IOException {
+    out.write(c);
+  }
+
+  public void write(byte[] b, int offset, int length) throws IOException {
+    out.write(b, offset, length);
+  }
+
+  public void flush() throws IOException {
+    out.flush();
+  }
+
+  public void close() throws IOException {
+    out.close();
+  }
+  
+}
diff --git a/classpath/java/io/ObjectStreamException.java b/classpath/java/io/ObjectStreamException.java
new file mode 100644
index 0000000000..f08ebed675
--- /dev/null
+++ b/classpath/java/io/ObjectStreamException.java
@@ -0,0 +1,11 @@
+package java.io;
+
+public class ObjectStreamException extends IOException {
+  public ObjectStreamException(String message) {
+    super(message);
+  }
+
+  public ObjectStreamException() {
+    this(null);
+  }
+}
diff --git a/classpath/java/io/OutputStreamWriter.java b/classpath/java/io/OutputStreamWriter.java
new file mode 100644
index 0000000000..827206db03
--- /dev/null
+++ b/classpath/java/io/OutputStreamWriter.java
@@ -0,0 +1,25 @@
+package java.io;
+
+public class OutputStreamWriter extends Writer {
+  private final OutputStream out;
+
+  public OutputStreamWriter(OutputStream out) {
+    this.out = out;
+  }
+  
+  public void write(char[] b, int offset, int length) throws IOException {
+    byte[] buffer = new byte[length];
+    for (int i = 0; i < length; ++i) {
+      buffer[i] = (byte) b[i + offset];
+    }
+    out.write(buffer);
+  }
+
+  public void flush() throws IOException {
+    out.flush();
+  }
+
+  public void close() throws IOException {
+    out.close();
+  }
+}
diff --git a/classpath/java/io/PrintWriter.java b/classpath/java/io/PrintWriter.java
new file mode 100644
index 0000000000..38659d3155
--- /dev/null
+++ b/classpath/java/io/PrintWriter.java
@@ -0,0 +1,46 @@
+package java.io;
+
+public class PrintWriter extends Writer {
+  private static final char[] newline
+    = System.getProperty("line.separator").toCharArray();
+
+  private final Writer out;
+  private final boolean autoFlush;
+
+  public PrintWriter(Writer out, boolean autoFlush) {
+    this.out = out;
+    this.autoFlush = true;
+  }
+
+  public PrintWriter(Writer out) {
+    this(out, false);
+  }
+
+  public synchronized void print(String s) {
+    try {
+      out.write(s.toCharArray());
+      if (autoFlush) flush();
+    } catch (IOException e) { }
+  }
+
+  public synchronized void println(String s) {
+    try {
+      out.write(s.toCharArray());    
+      out.write(newline);
+      if (autoFlush) flush();
+    } catch (IOException e) { }
+  }
+  
+  public void write(char[] buffer, int offset, int length) throws IOException {
+    out.write(buffer, offset, length);
+    if (autoFlush) flush();
+  }
+
+  public void flush() throws IOException {
+    out.flush();
+  }
+
+  public void close() throws IOException {
+    out.close();
+  }
+}
diff --git a/classpath/java/io/Reader.java b/classpath/java/io/Reader.java
new file mode 100644
index 0000000000..39737cffdb
--- /dev/null
+++ b/classpath/java/io/Reader.java
@@ -0,0 +1,22 @@
+package java.io;
+
+public abstract class Reader {
+  public int read() throws IOException {
+    char[] buffer = new char[1];
+    int c = read(buffer);
+    if (c <= 0) {
+      return -1;
+    } else {
+      return (int) buffer[0];
+    }
+  }
+
+  public int read(char[] buffer) throws IOException {
+    return read(buffer, 0, buffer.length);
+  }
+
+  public abstract int read(char[] buffer, int offset, int length)
+    throws IOException;
+
+  public abstract void close() throws IOException;
+}
diff --git a/classpath/java/io/Serializable.java b/classpath/java/io/Serializable.java
new file mode 100644
index 0000000000..2dab37587f
--- /dev/null
+++ b/classpath/java/io/Serializable.java
@@ -0,0 +1,3 @@
+package java.io;
+
+public interface Serializable { }
diff --git a/classpath/java/io/StringReader.java b/classpath/java/io/StringReader.java
new file mode 100644
index 0000000000..f2e2b82424
--- /dev/null
+++ b/classpath/java/io/StringReader.java
@@ -0,0 +1,23 @@
+package java.io;
+
+public class StringReader extends Reader {
+  private final String in;
+  private int position = 0;
+
+  public StringReader(String in) {
+    this.in = in;
+  }
+  
+  public int read(char[] b, int offset, int length) throws IOException {
+    if (length > in.length() - position) {
+      length = in.length() - position;
+      if (length <= 0) {
+        return -1;
+      }
+    }
+    in.getChars(position, length, b, offset);
+    return length;
+  }
+
+  public void close() throws IOException { }
+}
diff --git a/classpath/java/io/StringWriter.java b/classpath/java/io/StringWriter.java
new file mode 100644
index 0000000000..0e335d7b96
--- /dev/null
+++ b/classpath/java/io/StringWriter.java
@@ -0,0 +1,17 @@
+package java.io;
+
+public class StringWriter extends Writer {
+  private final StringBuilder out = new StringBuilder();
+  
+  public void write(char[] b, int offset, int length) throws IOException {
+    out.append(new String(b, offset, length));
+  }
+
+  public String toString() {
+    return out.toString();
+  }
+
+  public void flush() throws IOException { }
+
+  public void close() throws IOException { }
+}
diff --git a/classpath/java/io/Writer.java b/classpath/java/io/Writer.java
new file mode 100644
index 0000000000..98246ad0e1
--- /dev/null
+++ b/classpath/java/io/Writer.java
@@ -0,0 +1,19 @@
+package java.io;
+
+public abstract class Writer {
+  public void write(int c) throws IOException {
+    char[] buffer = new char[] { (char) c };
+    write(buffer);
+  }
+
+  public void write(char[] buffer) throws IOException {
+    write(buffer, 0, buffer.length);
+  }
+
+  public abstract void write(char[] buffer, int offset, int length)
+    throws IOException;
+
+  public abstract void flush() throws IOException;
+
+  public abstract void close() throws IOException;
+}
diff --git a/classpath/java/lang/String.java b/classpath/java/lang/String.java
index be3c72ab5e..f8153be92f 100644
--- a/classpath/java/lang/String.java
+++ b/classpath/java/lang/String.java
@@ -10,10 +10,18 @@ public final class String implements Comparable<String> {
     this((Object) data, offset, length, copy);
   }
 
+  public String(char[] data, int offset, int length) {
+    this(data, offset, length, true);
+  }
+
   public String(byte[] data, int offset, int length, boolean copy) {
     this((Object) data, offset, length, copy);
   }
 
+  public String(byte[] data, int offset, int length) {
+    this(data, offset, length, true);
+  }
+
   private String(Object data, int offset, int length, boolean copy) {
     if (copy) {
       Object c;
@@ -162,12 +170,6 @@ public final class String implements Comparable<String> {
     }
   }
 
-  public byte[] getBytes() {
-    byte[] b = new byte[length];
-    getBytes(0, length, b, 0);
-    return b;
-  }
-
   public void getBytes(int srcOffset, int srcLength,
                        byte[] dst, int dstOffset)
   {
@@ -186,6 +188,12 @@ public final class String implements Comparable<String> {
     }
   }
 
+  public byte[] getBytes() {
+    byte[] b = new byte[length];
+    getBytes(0, length, b, 0);
+    return b;
+  }
+
   public void getChars(int srcOffset, int srcLength,
                        char[] dst, int dstOffset)
   {
@@ -204,6 +212,12 @@ public final class String implements Comparable<String> {
     }
   }
 
+  public char[] toCharArray() {
+    char[] b = new char[length];
+    getChars(0, length, b, 0);
+    return b;
+  }
+
   public char charAt(int index) {
     if (index < 0 || index > length) {
       throw new IndexOutOfBoundsException();
diff --git a/classpath/java/lang/StringBuffer.java b/classpath/java/lang/StringBuffer.java
new file mode 100644
index 0000000000..080826efd0
--- /dev/null
+++ b/classpath/java/lang/StringBuffer.java
@@ -0,0 +1,39 @@
+package java.lang;
+
+public class StringBuffer {
+  private final StringBuilder sb = new StringBuilder();
+
+  public synchronized StringBuffer append(String s) {
+    sb.append(s);
+    return this;
+  }
+
+  public synchronized StringBuffer append(Object o) {
+    sb.append(o);
+    return this;
+  }
+
+  public synchronized StringBuffer append(int v) {
+    sb.append(v);
+    return this;
+  }
+
+  public synchronized StringBuffer append(long v) {
+    sb.append(v);
+    return this;
+  }
+
+  public synchronized int length() {
+    return sb.length();
+  }
+
+  public synchronized void getChars(int srcOffset, int srcLength, char[] dst,
+                                    int dstOffset)
+  {
+    sb.getChars(srcOffset, srcLength, dst, dstOffset);
+  }
+
+  public synchronized String toString() {
+    return sb.toString();
+  }
+}
diff --git a/classpath/java/lang/StringBuilder.java b/classpath/java/lang/StringBuilder.java
index a734bab1a6..68fbbb71d5 100644
--- a/classpath/java/lang/StringBuilder.java
+++ b/classpath/java/lang/StringBuilder.java
@@ -22,13 +22,40 @@ public class StringBuilder {
     return append(String.valueOf(v));
   }
 
-  public String toString() {
-    char[] array = new char[length];
+  public int length() {
+    return length;
+  }
+
+  public void getChars(int srcOffset, int srcLength, char[] dst, int dstOffset)
+  {
+    if (srcOffset + srcLength > length) {
+      throw new IndexOutOfBoundsException();
+    }
+
     int index = length;
     for (Cell c = chain; c != null; c = c.next) {
-      index -= c.value.length();
-      c.value.getChars(0, c.value.length(), array, index);
-    }
+      int start = index - c.value.length();
+      int end = index;
+      index = start;
+
+      if (start < srcOffset) {
+        start = srcOffset;
+      }
+
+      if (end > srcOffset + srcLength) {
+        end = srcOffset + srcLength;
+      }
+
+      if (start < end) {
+        c.value.getChars(start - index, end - start,
+                         dst, dstOffset + (start - srcOffset));
+      }
+    }    
+  }
+
+  public String toString() {
+    char[] array = new char[length];
+    getChars(0, length, array, 0);
     return new String(array, 0, length, false);
   }
 
diff --git a/classpath/java/lang/Throwable.java b/classpath/java/lang/Throwable.java
index 53ce5eac62..60b7595b85 100644
--- a/classpath/java/lang/Throwable.java
+++ b/classpath/java/lang/Throwable.java
@@ -1,5 +1,8 @@
 package java.lang;
 
+import java.io.PrintStream;
+import java.io.PrintWriter;
+
 public class Throwable {
   private String message;
   private Object trace;
@@ -42,10 +45,20 @@ public class Throwable {
     return (StackTraceElement[]) trace;
   }
 
-  public void printStackTrace() {
+  public void printStackTrace(PrintStream out) {
     StringBuilder sb = new StringBuilder();
     printStackTrace(sb, System.getProperty("line.separator"));
-    System.err.print(sb.toString());
+    out.print(sb.toString());
+  }
+
+  public void printStackTrace(PrintWriter out) {
+    StringBuilder sb = new StringBuilder();
+    printStackTrace(sb, System.getProperty("line.separator"));
+    out.print(sb.toString());
+  }
+
+  public void printStackTrace() {
+    printStackTrace(System.err);
   }
 
   private void printStackTrace(StringBuilder sb, String nl) {
diff --git a/classpath/java/net/MalformedURLException.java b/classpath/java/net/MalformedURLException.java
new file mode 100644
index 0000000000..7c10a3568a
--- /dev/null
+++ b/classpath/java/net/MalformedURLException.java
@@ -0,0 +1,11 @@
+package java.net;
+
+public class MalformedURLException extends Exception {
+  public MalformedURLException(String message) {
+    super(message);
+  }
+
+  public MalformedURLException() {
+    this(null);
+  }
+}
diff --git a/classpath/java/net/URL.java b/classpath/java/net/URL.java
new file mode 100644
index 0000000000..787b239ec0
--- /dev/null
+++ b/classpath/java/net/URL.java
@@ -0,0 +1,5 @@
+package java.net;
+
+public class URL {
+
+}