Object Pooling

Object Pooling, a common question, but with not easy to find solutions :

https://stackoverflow.com/questions/43735067/manage-client-socket-pool
https://stackoverflow.com/questions/939734/tips-for-using-commons-pool-in-production
https://github.com/roma/roma-java-client/blob/master/java/client/src/main/java/jp/co/rakuten/rit/roma/client/SocketPool.java

https://commons.apache.org/proper/commons-pool/
http://www.vibur.org/vibur-object-pool/
http://danielw.cn/fast-object-pool/

CEStreamExhausted anti-pattern

This exception is thrown when EOF is found. Literally is an anti-pattern (like a goto)

https://github.com/openjdk-mirror/jdk7u-jdk/blob/master/src/share/classes/sun/misc/CEStreamExhausted.java

/** This exception is thrown when EOF is reached */
public class CEStreamExhausted extends IOException { };

Which is executed at line 117 de BASE64Decoder :

https://github.com/openjdk-mirror/jdk7u-jdk/blob/master/src/share/classes/sun/misc/BASE64Decoder.java

do {
   i = inStream.read();
   if (i == -1) {
      throw new CEStreamExhausted();
   }
} while (i == '\n' || i == '\r');

Therefore it's a false-positive if any APM raise it.

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Me faltó agregar que la clase que llama a la lanza la excepcion en cuestion es: CharacterDecoder.java

https://github.com/openjdk-mirror/jdk7u-jdk/blob/master/src/share/classes/sun/misc/CharacterDecoder.java

Y lo que hace es tener un loop infinito while(true) que se sale de ahi al atrapar dicha exception.

Por lo tanto queda demostrado que es un falso-positivo.

while (true) {
	int length;
	try {
	length = decodeLinePrefix(ps, bStream);
	for (i = 0; (i+bytesPerAtom()) < length; i += bytesPerAtom()) {
	decodeAtom(ps, bStream, bytesPerAtom());
	totalBytes += bytesPerAtom();
	}
	if ((i + bytesPerAtom()) == length) {
	decodeAtom(ps, bStream, bytesPerAtom());
	totalBytes += bytesPerAtom();
	} else {
	decodeAtom(ps, bStream, length - i);
	totalBytes += (length - i);
	}
	decodeLineSuffix(ps, bStream);
	} catch (CEStreamExhausted e) {
	break;
	}

Log4j config ?

A way to check if log4j is configurated at runtime.

log4j IsConfigured ::: 

    /**
     * Returns true if it appears that log4j have been previously configured. This
     * code checks to see if there are any appenders defined for log4j which is the
     * definitive way to tell if log4j is already initialized
     */
    private static boolean isConfigured() {
        Enumeration appenders = Logger.getRoot().getAllAppenders();
        if (appenders.hasMoreElements()) {
            return true;
        } else {
            Enumeration loggers = LogManager.getCurrentLoggers();
            while (loggers.hasMoreElements()) {
                Logger c = (Logger) loggers.nextElement();
                if (c.getAllAppenders().hasMoreElements())
                    return true;
            }
        }
        return false;
    }


http://wiki.apache.org/logging-log4j/UsefulCode
http://logging.apache.org/log4j/1.2/xref-test/org/apache/log4j/defaultInit/TestCase4.html
https://web.archive.org/web/20130401061324/http://dsiutils.dsi.unimi.it/
https://web.archive.org/web/20081211154329/http://dsiutils.dsi.unimi.it/docs/it/unimi/dsi/Util.html
https://web.archive.org/web/20110303190435/http://www.screaming-penguin.com/node/7622