Core Java Tutorials, Core Java Programming Tips, Simple Core Java Tutorial
Since every thread runs in it’s own stack in java the main thread will not come to know the status of Thread started by it. Programmer can implement an interface named UncaughtExceptionHandler to get a call back from JVM if an Exception occurs in a given thread and its not handled properly. A simple implementation […]
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All of you would be knowing the fact that String is immutable in java, which means once constructed can not be altered. This allows the jvm to have a literal pool, literal pool will be helpful to reduce the memory usage and to increase the performance. Each time when a String is created JVM check […]
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Java util package provides us number of sorted data structures; one of those is the TreeSet. TreeSet is an implementation of Set and it stores the elements in sorted order. All elements needs to be added into a TreeSet should implement Comparable interface directly or indirectly or the TreeSet should be constructed with an appropriate […]
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You know the power of pipe (“|”) operator in Unix. It helps you to redirect output from one command to another. PipedReader and PipedWriter classes in java.io package helps you to do the same. It helps you to redirect the read input into writer seamlessly. In unix, two process on different address space can communicate […]
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When multiple threads work on a shared resource its quiet possible that one thread’s work is over written by another one if the shared resource is modified without a mutually exclusive lock. This can be solved by moving the code responsible for the state change of the shared resource into a synchronized method/block. What if […]
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There is a tool called javap to find out the compiler version and much more from a class file. See the below given console output to get more details. javap is located in %JAVA_HOME%/bin.
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opt/mnt/javap -verbose JNDIClientExample Compiled from "JNDIClientExample.java" public class org.sanju.JNDIClientExample extends java.lang.Object SourceFile: "JNDIClientExample.java" minor version: 0 major version: 50 Constant pool: const #1 = class #2; // org/sanju/JNDIClientExample const #2 = Asciz org/sanju/JNDIClientExample; const #3 = class #4; // java/lang/Object const #4 = Asciz java/lang/Object; Below given details will help you to map a major version into JDK version. 1.1 (major version: 45 minor: 3) 1.2 (major version: 46 minor: 0) 1.3 (major version: 47 minor: 0) 1.4 (major version: 48 minor: 0) 1.5, 5 or 5.0 (major version: 49 minor: 0) 1.6, 6 or 6.0 (major version: 50 minor: 0) |
If you want to list out all files from a given directory or drive you can use the list method in the java.io.File class. Consider a scenario where you wanted to list out all files with specific extension. FileFilter interface will help you to filter files using any criteria you can imagine. Today we will […]
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You might want to take the Thread dump of JVM instance to check the state of your threads if its stop responding. In linux you can use “kill -QUIT process_id” of the JVM instance to get the thred dump. Thread dump can give you details like state of all threds in the JVM and the […]
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