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  try { return } finally {}

Do you know what value will be printed when following program is ran? class Test { public int aaa() { int x = 1; try { return ++x; } catch (Exception e) { } finally { ++x; } return x; } public static void main(String[] args) { Test t = new Test(); int y = t.aaa(); System.out.println(y); } } And before answering the above question, do you have answers to following questions? If ther...

   JAVA,JAVA INTERVIEW QUESTION     2016-09-26 08:06:28

  What does super.clone() do?

Object class has a protected clone() method declared to make it possible for all classes make a clone of itself when needed. The clone() is often used when a new instance of the class is needed while at the same time to maintain the same state as the original object. Any class which wants to have clone enabled has to implement the marker interface Cloneable. If a class which implements Cloneable doesn't override the Object.clone() method, the Object.clone() method will be called to just make a b...

   Cloneable,super.clone(),clone,Java     2015-01-07 05:25:52

  Use of log in programming

Usually, The purposes of log are for troubleshooting and displaying program running status. Good log will help us locate the error easier. Many programmers think log in programs is very simple, but it's not an easy task to write log codes to efficiently locate the error. Here we discuss about program log in three aspects: Where to log What to log Log styles to be avoided Where to log 1. When calling external functions When your program is calling some external functions which are not written b...

   Log, Programming,Debug     2012-11-28 11:42:23

  Use Memory Analyzer Tool in Eclipse

When developing applications, we often encounter memory issues of an application. To analyze how much memory each class takes, we need to have some specific tools to assist us. One of them is Memory Analyzer Tool on Eclipse. The Eclipse Memory Analyzer is a fast and feature-rich Java heap analyzer that helps you find memory leaks and reduce memory consumption. To use the Memory Analyzer Tool, you first need to install it on Eclipse. You can go to Help -> Install New Software.... Paste  h...

   Memory analyzer tool, Eclipse,heap dump, HPROF     2014-10-28 07:22:35

  Why exception would be thrown when deleting element while looping through HashMap in Java

HashMap and other Collection types are frequently used in Java application programming. This post will explain why exception would be thrown when deleting element with Map.remove() while looping through a Map using Iterator. This issue would also occur to other Collection types such as Set, List. Below is a sample code snippet demonstrating the exception thrown. Map<String,String> map = Collections.synchronizedMap(new TreeMap<String,String>()); map.put("key1","value1"); map.put("ke...

   JAVA,HASHMAP,CONCURRENTMODIFICATIONEXCEPTION     2018-06-30 12:49:09

  The difference between System.load and System.loadLibrary in Java

When writing code using native library in Java, normally the first step is loading some native library. static{ 　　System.load("D:" + File.separator + "Hello.dll"); } JDK provides two ways to load libraries: System.load(String filename) System.loadLibrary(String libname) This post will try to explain the differences of these two ways. According to Java Doc on System.load(), it has below description. Loads the native library specified by the filename argument. The filename a...

   NATIVE,JNI,JAVA,SYSTEM.LOAD,SYSTEM.LOADLIBRARY     2019-02-05 05:49:28

  Using MemoryMappedBuffer to handle large file in Java

When handling large files, it will largely affect the process speed while using traditional FileInputStream, FileOutputStream or RandomAccessFile since they trigger lots of read and write operations. In Java NIO, a new way of handling large file is introduced which is to use MmeoryMappedBuffer to create memory mapped file. Memory-mapped I/O uses the filesystem to establish a virtual memory mapping from user space directly to the applicable filesystem pages. With a memory-mapped file, you can pre...

   JAVA,IO,NIO     2015-11-13 01:58:08

  Generate certificate in Java -- Certificate chain

In previous post, we have introduced the use of Certificate and how to generate self signed certificate using Java. In this post, we will show you how to generate a certificate chain. Sometimes we may only have a certificate request or we don't have a trusted certificate which can be used for business. Now we need to have a trusted CA to sign our certificate so that it can be used on SSL communications. To generate a certificate chain, we may first have our own certificate(A), then we may use ot...

   Java,Certificate chain,Creation, Pure Java     2014-07-30 08:24:52

  How to make select in WinSock exceed the 64-socket limit

When doing cross-platform network programming, the only API available on Windows that corresponds to the epoll/kevent style reactor event model is select. However, it has a limitation: the number of sockets passed into select cannot exceed FD_SETSIZE, which is set to 64. Therefore, select in Java’s NIO on Windows also has the same limit. Many services ported to Windows that use the reactor model face this constraint, which often gives the impression that server programs on Windows hav...

   EXCEED,SELECT,JAVA,WINDOWS     2024-10-31 23:47:50

  Python Disrupts the Programming Language World- Gets Hot and Popular

Python is one of the fastest growing languages currently. It is undeniable that more and more programmers use Python and deploy it to the best of their use. Everyone, from the freelancer and startups to giant corporations and even governments, is using Python. Let us have a look at the reasons that make it so popular.  Training: According to research, 8 out of 10 tech schools in the US teach Python over JAVA. Even the three major MOOC platforms, edX, Coursera, and Udacity have a similar app...

   DEVELOPMENT,PYTHON,TEAM     2018-06-07 01:02:03

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