question: public static final void readFully ( InputStream is , byte [ ] buffer , int offset , int len ) throws IOException { int temp ; while ( len > 0 ) { temp = is . read ( buffer , offset , len ) ; if ( temp == - 1 ) throw new EOFException ( "Cannot read all " + len + " bytes needed to form this token!" ) ; offset += temp ; len -= temp ; } }
target:  Blocks till the required number of bytes have been read from the input stream.