JDK优化

其中的DataSource
               方法基本是： 

try { 
    synchronized (lock) { 
ensureOpen(); 
out.write(s, off, len); 
    } 
} 
catch (InterruptedIOException x) { 
    Thread.currentThread().interrupt(); 
} 
catch (IOException x) { 
    trouble = true; 
} 



public void write(String str, int off, int len) throws IOException { 
synchronized (lock) { 
    char cbuf[]; 
    if (len <= writeBufferSize) { 
if (writeBuffer == null) { 
    writeBuffer = new char[writeBufferSize]; 
} 
cbuf = writeBuffer; 
    } else {	// Don't permanently allocate very large buffers. 
cbuf = new char[len]; 
    } 
    str.getChars(off, (off + len), cbuf, 0); 
    write(cbuf, 0, len); 
} 
    } 

继续可学，做个记录未完事情