diff --git a/tls/src/main/java/com/iluwatar/tls/AppUgly.java b/tls/src/main/java/com/iluwatar/tls/AppUgly.java deleted file mode 100644 index 7025d42b7..000000000 --- a/tls/src/main/java/com/iluwatar/tls/AppUgly.java +++ /dev/null @@ -1,112 +0,0 @@ -/** - * The MIT License - * Copyright (c) 2016 Thomas Bauer - * - * Permission is hereby granted, free of charge, to any person obtaining a copy - * of this software and associated documentation files (the "Software"), to deal - * in the Software without restriction, including without limitation the rights - * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell - * copies of the Software, and to permit persons to whom the Software is - * furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice shall be included in - * all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE - * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, - * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN - * THE SOFTWARE. - */ - -package com.iluwatar.tls; - -import java.util.ArrayList; -import java.util.Calendar; -import java.util.Collections; -import java.util.Date; -import java.util.List; - -/** - * - * This App shows an example for problems with global thread variables. A global - * thread variable is a variable defined as class variable of a - * XyzRunnable-Class. In this example in the class - * {@link DateFormatUglyRunnable} - *

- * Example use case: A well known problem with threads are non thread-safe Java - * classes. One example is the class SimpleDateFormat. - *

- * In the example an instance of SimpleDateFormat is created in the constructor - * of the Runnable. The constructor initializes a class variable with the - * instance. The Runnable only does convert a string date to a date format using - * the instance of SimpleDateFormat. It does this 5 times. - *

- * In the example 4 threads are started to do the same. If you are lucky - * everything works well. But if you try more often you will happen to see - * Exceptions. And these Exceptions arise on arbitrary points of the run. - *

- * The reason for this exceptions is: The threads try to use internal instance - * variables of the SimpleDateFormat instance at the same time (the date is - * stored internal as member variable during parsing and may be overwritten by - * another thread during a parse is still running) - *

- * And even without Exceptions the run may not deliver the correct results. - * All date values should be the same after the run. Check it - * - */ -public class AppUgly { - // A list to collect the date values created in the the threads - static List dateList = Collections.synchronizedList(new ArrayList()); - // A list to collect Exceptions thrown in the threads - static List exceptionList = Collections.synchronizedList(new ArrayList()); - - /** - * Program entry point - * - * @param args - * command line args - */ - public static void main(String[] args) { - int counterDateValues = 0; - int counterExceptions = 0; - - // Prepare the Runnable - DateFormatUglyRunnable runnableDf = new DateFormatUglyRunnable("dd/MM/yyyy", "15/12/2015"); - - // 4 threads using the same Runnable - Thread t1 = new Thread(runnableDf); - Thread t2 = new Thread(runnableDf); - Thread t3 = new Thread(runnableDf); - Thread t4 = new Thread(runnableDf); - t1.start(); - t2.start(); - t3.start(); - t4.start(); - try { - t1.join(); - t2.join(); - t3.join(); - t4.join(); - } catch (InterruptedException e) { - // Action not coded here - } - for (Date dt : dateList) { - // a correct run should deliver 20 times 15.12.2015 - counterDateValues++; - Calendar cal = Calendar.getInstance(); - cal.setTime(dt); - // Formatted output of the date value: DD.MM.YYYY - System.out.println(cal.get(Calendar.DAY_OF_MONTH) + "." + cal.get(Calendar.MONTH) + "." + cal.get(Calendar.YEAR)); - } - for (String ex : exceptionList) { - // a correct run shouldn't deliver any exception - counterExceptions++; - System.out.println(ex); - } - System.out.println("The List dateList contains " + counterDateValues + " date values"); - System.out.println("The List exceptionList contains " + counterExceptions + " exceptions"); - } -}