Index: luni/src/main/java/java/io/OutputStreamWriter.java =================================================================== --- luni/src/main/java/java/io/OutputStreamWriter.java (revision 485590) +++ luni/src/main/java/java/io/OutputStreamWriter.java (working copy) @@ -84,7 +84,9 @@ public OutputStreamWriter(OutputStream out, final String enc) throws UnsupportedEncodingException { super(out); - enc.length(); + if(enc == null) { + throw new NullPointerException(); + } this.out = out; try { encoder = Charset.forName(enc).newEncoder(); Index: luni/src/main/java/java/io/InputStreamReader.java =================================================================== --- luni/src/main/java/java/io/InputStreamReader.java (revision 485590) +++ luni/src/main/java/java/io/InputStreamReader.java (working copy) @@ -91,7 +91,9 @@ public InputStreamReader(InputStream in, final String enc) throws UnsupportedEncodingException { super(in); - enc.length(); + if(enc == null) { + throw new NullPointerException(); + } this.in = in; try { decoder = Charset.forName(enc).newDecoder()