Top Most How to attach source in eclipse for Jars, debugging and code look-up – JDK Example

Attaching source of any Jar in Eclipse e.g. JDK or open source libraries like Spring framework is good idea because it help during debugging and code development. As a Java programmer at least you should attach source of JDK in Eclipse IDE to find out more about JDK classes. Though Eclipse IDE is pretty good on code assist, sometime You want to know what's going inside a library or a JDK method, rather than just reading documentation. Interview questions like How HashMap works in Java or How substring cause memory leak can only be answered if you are familiar with source code of these classes.  Once you attach source code of Java or Spring in Eclipse IDE, You can check code with just a single click. Some one may argue for Java decompiler like JAD which can create source from .class file which is also a smart way to look code for open source library, but decompiled source file is not same as original source file, as you lost comment and readability. As per my experience attaching source code corresponding to JAR file is much better than decompiling a class file using JAD decompiler. 

Read more »

Top Most 10 Tips to override toString() method in Java - ToStringBuilder Netbeans Eclipse

Java toString method

toString method in Java is used to provide clear and concise information about Object in human readable format. Correctly overridden toString method can help in loggingand debugging of Java program by providing valuable and meaningful information. Since toString() is defined in java.lang.Object class and its default implementation doesn't provide much information, its always a best practice to override toString method in sub class. In fact if you are creating value class or domain class e.g. Order, Trade or Employee,  always override equals, ,hashCode, compareToand toString method in Java.  By default toStringimplementation produce output in the form package.class@hashCode e.g. for our toString() example, Country class’ toString() method will print test.Country@18e2b22 where 18e2b22 is hashCode of object in hex format, if you call hashCode method it will return 26094370, which is decimal equivalent of 18e2b22. This information is not very useful while troubleshooting any problem. Let’s see a real life example where you are troubleshooting network connectivity issues, in case of this you want to know which host and port your system is trying to connect and if Socket or ServerSocket class only print default toString information than its impossible to figure out the actual problem, but with a decent toStringimplementation they can print useful information like hostname and port. In this Java  tutorial we will see some tips to override toString method with code examples.

Read more »