Simple Java Tips

Write compressing rolling file appender for log4j

2009-08-31T21:45:00.001-07:00

Good day! On the last week, we gave our software to support specialists. They installed the program to production servers. And over three thousand users began to work with it. At the on of that week, I didn't hear nothing about our product. This is good the good sign! :) But, we have one little problem, log file that wrote program had size little more 1Gb!!! This is not very good result :)

Increase perfomance for insert operations to database

2009-07-01T21:56:00.000-07:00

Hi all!In this post, I would like to tell about the way to optimize INSERT operation to database. In our project we use postgresql 8.3. I have big problems with speed on some operations. When I profiled the application, I find out that the biggest amount of time spent for JDBC operations. We getting data from external systems, and often we have more than 300000 inserts to table. For work with

Create hyperlink with browsing support.

2009-04-21T21:03:00.000-07:00

Yesterday, one of my tasks was to display hyperlink to local file. When user clicks hyperlink, program have to open file in an associated application. Earlier I have been writing desktop applications on QT and I haven't had any problems. But it is not very simple in Java(Swing). First, I've created label and put html as text:JLabel label = new JLabel("link");When

test syntax highlighter for blogger

2009-04-19T13:07:00.000-07:00

public class SimpleClass { public SimpleClass() { System.out.println("I'm a simple class!!!"); }}If you want the same highlighter in your blogger:1.Install widget from here: http://fazibear.googlepages.com/blogger.html2.Reading usage instruction(and do it:)) from here: http://code.google.com/p/syntaxhighlighter/wiki/UsageBig thanks to developers of syntaxhighlighter.

Using inner classes

2009-04-12T07:23:00.001-07:00

Hi all! In this post I want to tell you about inner classes. Very often, we create static inner classes that contains information about main class. For example: public class Person { private String name; private String occupation; public static class PersonInfo { private String info; public PersonInfo(String name, String occupation) { info = “His name is ” + name + “ . He is

Debug JNLP application

2009-01-18T07:05:00.000-08:00

Hi all!I want to remote debug in jnlp application. This problem solved is very simple. I set environment variable JAVAWS_VM_ARGS to value: -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=5006After this, I create new run point in Intelli J IDEA. Type of run point is Remote debug. In run point set set host=localhost and port=5006(or other, ports in JAVAWS_VM_ARGS and run point must

Global security in WAS 6.1over Active Directory

2008-12-13T06:42:00.001-08:00

We need security over Active Directory in our enterprise application wich works on WebSphere Application Server v 6.1.x. When we test our application we use OpenDS(https://opends.dev.java.net/) to emulate Active Directory. But we must replace OpenDS with Active Directory. Every LDAP server has specific parameters. For fast test, I use ldapsearch from OpenDS. I spent more then two hours to get

SVN: Update only new folders in working copy

2008-12-05T22:55:00.000-08:00

Hi all!For example, you have working copy that looks like this:foo/bar/And you know that someone added new folder, that called baz, in repository. You want get only this folder and you don't want to update all working copy. Solution is very simple:C:\project\>svn update bazThat's all, now you have new folder in your working copy.P.S. You can't do this, using popular frontend for svn - TortoiseSVN.

Placeholder trick in Spring

2008-11-20T03:35:00.001-08:00

Hello everyone! In the Spring Framework (I use Spring 2.5), we can use property placeholders in the spring xml-based configuration file. I wrote simple example that consist of four beans. Two of them are simple beans, one is a factory and one is a result bean that we want to get from factory bean.

Reading from InputStream

2008-11-05T22:23:00.001-08:00

Lately I've faced a simple problem: I needed to read all bytes from the InputStream. I didn't know type of the InputStream, so, I've spent more then two hours solving this problem without any success. I didn't want to read each byte from the stream. All evening I could think only about this problem. Solution turned to be very simple! I found a sample in the JDK installation directory($JAVA_HOME/

Using reflections for test equals.

2008-10-06T21:48:00.000-07:00

Problem: test for equals two objects of the same class by all fields(deep equals). For solve this problem I use reflection API from JDK. Package that store classes for reflection is java.lang.reflect. I wrote simple helper class with static methods. You can find the complete realization at the and of the post. First of all we should describe algorithm: Input: two object that we need compare.

Connect to mysql 5 with Tomcat 6

2008-09-28T10:37:00.000-07:00

When I try to solve this problem I read two docs: help in Netbeans 6(http://www.netbeans.org/kb/60/web/mysql-webapp.html#settingUpConnPool) and jndi help from tomcat.apache.org(http://tomcat.apache.org/tomcat-6.0-doc/jndi-datasource-examples-howto.html). But when I lookup InitialContext, application throws NamingException. I spent over four hours to solve this problem. As I've understood, when I

Wrapper for JComponent

2008-09-15T21:59:00.000-07:00

Trouble: we have some JComponent. We need paint this component and remove all logic from it.At the begining, I think that solution is very simple: override paint() method, and draw inner component in wrpapper's Graphics.public class ComponentWrapper extends JComponent { private JComponent innerComponent; public ComponentWrapper(JComponent innerComponent) { this.innerComponent =