How to setup Java remote debugging in Eclipse

How to remote debug Java program in Eclipse
Remote debugging is not a new concept and many of you are aware of this just for who don’t know what is remote debugging? It’s a way of debugging any process could be Java or C++ running on some other location on your development machine.  Since debugging Java application is an essential part of Java development and ability to debug your application not only saves time but also increase productivity. Local debugging is the best way to debug Java program in my opinion and should always be preferred over remote debugging as discussed in my post How to debug Java program in Eclipse, but if local debugging is not possible and there is no way to debug your process then remote debugging Java application is the solution.  

All Major IDE like NetBeans, Eclipse, IntelliJ allows you to remote debug Java program but I mostly use Eclipse for remote debugging Java application because it's free and standard IDE in Investment banks for Java projects. By the this is second article on Eclipse IDE in Javarevisited after sharing Top 30 Eclipse keyboard shortcuts to improve productivity in the previous post.

Overriding equals() and hashCode() method in Java and Hibernate

Override equals and hashCode in Java
Equals and hashCode in Java are two fundamental methods which are declared in Object class and part or core Java library. equals() method is used to compare Objects for equality while hashCode is used to generate an integer code corresponding to that object. equals and hashCode have used extensively in Java core library like they are used while inserting and retrieving Object in HashMap, see how to get method of HashMap works in Java for the full story, equals method is also used to avoid duplicates on HashSet and other Set implementation and every other place where you need to compare Objects. Default implementation of equals() class provided by java.lang.Object compares memory location and only return true if two reference variable is pointing to same memory location i.e. essentially they are the same object. Java recommends to override equals and hashCode method if equality is going to be defined by logical way or via some business logic and many classes in Java standard library does override it e.g. String overrides equals,  whose implementation of equals() method return true if the content of two String objects is exactly same. Integer wrapper class overrides equal to perform numerical comparison etc.

How to execute native shell commands from Java Program

How to execute native shell commands from JAVA
Though it’s not recommended but some time it’s become necessary to execute native operating system or shell command from JAVA, especially if you are doing some kind of reporting or monitoring stuff and required information can easily be found using native command. This is not advised though because then you will lose platform independence which is why we mostly used JAVA.

Anyway if you no choice and you want to execute native commands from JAVA then its good to know that how we can do it, many of you probably know this but for those who don't know and have never done it we will see through an example.

FIX Protocol tutorials: Difference between Session Level Reject and Business message Reject

FIX Protocol tutorials: Difference between Session Level Reject and Business message Reject
In FIX protocol there are multiple ways of rejecting message some of them are using an Execution Report (MsgType=8) and ExecType=8 to reject a FIX message if it can not be acceptable by exchange e.g. Sending order for an exchange and link between broker and exchange is down. Another way of rejecting message is OrderCancelReject (FIX MsgType=9) which is used to reject amend (OrderCancelReplace message FIX MsgType 35=G) and cancel (OrderCancelRequest FIX MsgType=F) messages if its not possible to modify or cancel original message e.g. Sending Cancel request to an already filled order will be rejected by OrderCancelReject message in FIX protocol.

Repeating groups in FIX Protocol

FIX Protocol repeating group
In this FIX protocol tutorial, I am going to share my experience about FIX repeating block or group. This is a fundamental concept of FIX protocol and used to carry repeating data. A correct understanding of various available FIX repeating groups e.g. PartyID block, Allocation repeating group etc is very important for writing FIX based software. In this FIX tutorial, I will explain about how to parse a repeating group, how to prepare a repeating group and how to understand a repeating group. If you like to know more about basic concepts in FIX protocol then you may find my FIX Protocol tutorial interesting.

TIBCO Ledger file in Certified messaging : TIBCO Tutorial

TIBCO Ledger files in certified messaging
This is in continuation to my previous article on TIBCO Certified messaging, in this TIBCO tutorial we will discuss about what is TIBCO ledger? What is process based ledger and what is file based ledger?  Which messages are stored in TIBCO ledger? What are advantage and disadvantage of using TIBCO ledger? When should we use Process based and File based ledger etc. if you would like to read my earlier TIBCO Tutorial please see.

How to Implement Thread in Java with Example

How to implement Thread in Java
In my opinion, Thread is one of the most important features of Java programming language which helped it to become the most popular programming language. I remember, when I first started learning Java in one of the programming class in India how important Thread was portrait and how much emphasis given on clear understanding of multi-threading. It’s still popular and one of most sought after skill in Java programmer because writing concurrent and multi-threaded application in Java is challenging, despite Java providing excellent support at language level using synchronized and volatile keyword. Main problem with using multiple threads and writing multi-threaded code is issues related to concurrency e.g. deadlock, livelock, race conditions etc, It takes lot of effort to implement multi-threading correctly in Java application.

FIX Protocol Session or Admin messages tutorial

FIX Protocol Session or Admin messages tutorial
I have been working on FIX protocol for almost 5 years when I started working on FIX protocol I looked upon internet for some good tutorial which could supplement or complement lengthy FIX protocol specification there was nothing at that time so when I started my blog I thought to write about my own experience in FIX protocol as short, clear and concise tutorial format. Since I like question answer type of knowledge sharing too I have written some blog post on FIX protocol Interview questions you may find it interesting. In today’s FIX tutorial we are going to have a look on FIX protocol session level messages. As you guys may know all FIX messages can be broadly classified into two categories Admin messages also called session level messages and Application messages which include Trade, pre trade and post trades messages.

Introduction to Tibco Hawk as Tibco Tutorial

Tibco Hawk
This is another short  TIBCO tutorial from my TIBCO tutorial series. in this i am gonna discuss what is TIBCO hawk , Where do we use TIBCO hawk , What are components of TIBCO hawk , what benefit TIBCO hawk offers and how Tibco hawk works.  if you are interested to know more about TIBCO  Rendezvous , TIBCO EMS and there fundamental concept  or if you are looking for some TIBCO Interview questions you may find this link interesting TIBCO Tutorial

How HashMap works in Java

HashMap in Java works on hashing principle. It is a data structure which allows us to store object and retrieve it in constant time O(1) provided we know the key. In hashing, hash functions are used to link key and value in HashMap. Objects are stored by calling put(key, value) method of HashMap and retrieved by calling get(key) method. When we call put method, hashcode() method of the key object is called so that hash function of the map can find a bucket location to store value object, which is actually an index of the internal array, known as the table. HashMap internally stores mapping in the form of Map.Entry object which contains both key and value object. When you want to retrieve the object, you call the get() method and again pass the key object. This time again key object generate same hash code (it's mandatory for it to do so to retrieve the object and that's why HashMap keys are immutable e.g. String) and we end up at same bucket location. If there is only one object then it is returned and that's your value object which you have stored earlier. Things get little tricky when collisions occur. It's easy to answer this question if you have read good books on data structure and algorithms like this one. If you know how hash table data structure works then this is a piece of cake.