Performance Tip: Use StringBuilder instead of String for a non constant field.

Overview

Appending to a String is much slower than appending to a StringBuilder.

Append to a StringBuilder

From Logger.entering()
String msg = "ENTRY"; // later for (int i = 0; i < params.length; i++) { msg = msg + " {" + i + "}"; }
Inside the loop it creates a StringBuilder and another String every time. It can be replaced with code which creates one StringBuilder and String, total. 
StringBuilder msgSB = new StringBuilder("ENTRY"); // later for (int i = 0; i < params.length; i++) { msgSB.append(" {").append(i).append("}"); } String msg = msgSB.toString();

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