If you are a Java Expert then this is for you. Let us know if you looking for a job change? Then do not worry, we’ve a right answer for your job interview preparation. If you are preparing for Java J2ee Architect job interview and don’t know how to crack interview and what level or difficulty of questions to be asked in job interviews then go through Wisdomjobs interview questions and answers page to crack your job interview. Architect has responsibility for ensuring coherence of all aspects of the project as an integrated system. Architect is responsible for overall technical quality, developer for lower implementation decisions. Below are the Java J2ee Architect interview questions and answers which makes you comfortable to face the interviews:
No, Java runs on a virtual machine called JVM and hence doesn't embed well with the underlying hardware. Though we can create a platform independent system software but that would be really slow and that's what we would never need.
Class , Heap , Stack , Register , Native Method Stack.
Bootstrap - Loads JDK internal classes, java.* packages.
Extensions - Loads jar files from JDK extensions directory - usually lib/ext directory of the JRE
System - Loads classes from system classpath.
The memory pool containing all the reflective data of the java virtual machine itself, such as class and method objects. With Java VMs that use class data sharing, this generation is divided into read-only and read-write areas. The Permanent generation contains metadata required by the JVM to describe the classes and methods used in the application. The permanent generation is populated by the JVM at runtime based on classes in use by the application. In addition, Java SE library classes and methods may be stored here.
The Permanent Generation (PermGen) space has completely been removed and is kind of replaced by a new space called Metaspace. The consequences of the PermGen removal is that obviously the PermSize and MaxPermSize JVM arguments are ignored and you will never get a java.lang.OutOfMemoryError: PermGen error.
Volatile is an instruction that the variables can be accessed by multiple threads and hence shouldn't be cached. As volatile variables are never cached and hence their retrieval cannot be optimized.
The best practice guideline between settings.xml and pom.xml is that configurations in settings.xml must be specific to the current user and that pom.xml configurations are specific to the project.
Simplest implementation we can have is a List wherein we can place ordered words and hence can perform Binary Search.
Other implementation with better search performance is to use HashMap with key as first character of the word and value as a LinkedList.
Further level up, we can have linked Hashmaps like ,
a ( key ) -> hashmap (key-aa , value (hashmap(key-aaa,value)
b ( key ) -> hashmap (key-ba , value (hashmap(key-baa,value)
z( key ) -> hashmap (key-za , value (hashmap(key-zaa,value)
upto n levels ( where n is the average size of the word in dictionary.
When multiple external resources are trying to access the DB locks and runs into cyclic wait, it may makes the DB unresponsive.
Deadlock can be avoided using variety of measures, Few listed below:
With the advent of Internet, HTTP is the most preferred way of communication. Most of the clients ( web thin client , web thick clients , mobile apps ) are designed to communicate using http only. Web Services using http makes them accessible from vast variety of client applications.
Session info in the request can be intercepted and hence a vulnerability. Cookie can be read and write by respective domain only and make sure that right session information is being passed by the client.
Lambda Expressions , Interface Default and Static Methods , Method Reference , Parameters Name , Optional , Streams, Concurrency.
Question 18. If You Are Given A Choice To Implement The Code To Either Insert A Record Or Update If Already Exist, Which Approach Will You Follow ? 1. Insert Into The Db Table. If Exception Occurs, Update The Existing Record. 2. Check If The Record Exists And Update It If It Exists, If Not Insert A New Record.
In first case, there would be 2 DB calls in worst case and 1 in best case. In 2nd approach there will be always 2 DB calls.
Decision on the approach should depend on the following considerations -
1. How costly is the call to DB. Are we using indices , hibernate etc
If calls to DB are costly , 1st approach should be the choice.
2. Exception Book keeping load upon exception.
The benefit of saving 1st call in approach 1 should be bigger than the Book keeping for the exception.
3. Probability of the exception in first apparoach.
If the DB Table is almost empty, it makes sense to follow Approach 1 as majority of the 1st calls will pass through without exception.
If its already there in Maven local repository, We can add that as a dependency in the project pom file with its Group Id, Artifact Id and version.
We can provide additional attribute SystemPath if its unable to locate the jar in the local repository.
If its not there in the local repository, we can install it first in the local repository and then can add it as dependency.
Use Case Diagram, Component Diagram for High level Design and Class Diagram , Sequence Diagram for low level design.
We as a team of developers , testers , analyst , lead and architect sit close to each other. Most of the time I would just jump to their seat and talk to them ( if required ). We have daily stand up where we discuss things that needs team attention.
We have multi tier architecture with multiple layers , We have series of web servers and applications in application tier, infrastructure libraries at middle tier and Database servers at the lower tier. We are using Oracle as Database, ESB ( Enterprise service Bus ) for asynchronous communication and Rest Web Services.
Adapter object has a different input than the real subject whereas Proxy object has the same input as the real subject. Proxy object is such that it should be placed as it is in place of the real subject.
The Difference between these patterns in only the intent. Adapter is used because the objects in current form cannot communicate where as in Facade , though the objects can communicate , A Facade object is placed between the client and subject to simplify the interface.
Builder is a creational Design Pattern whereas Composite is a structural design pattern. Composite creates Parent - Child relations between your objects while Builder is used to create group of objects of predefined types.
Factory is a creational design pattern whereas Strategy is behavioral design pattern. Factory revolves around the creation of object at runtime whereas Strategy or Policy revolves around the decision at runtime.
Strategy deals only with decision making at runtime so Interfaces should be used.
Java J2ee Architect Related Tutorials
|Java Script Tutorial||Adv Java Tutorial|
|Core Java Tutorial||Hibernate Tutorial|
|JavaServer Faces (JSF) Tutorial||Java 8 Tutorial|
|JavaFX Tutorial||NHibernate Tutorial|
|Spring MVC Framework Tutorial||The Java Debugger (JDB) Tutorial|
|Java.math Package Tutorial|
Java J2ee Architect Related Interview Questions
|Java Script Interview Questions||Adv Java Interview Questions|
|J2SE Interview Questions||Core Java Interview Questions|
|Java Struts Interview Questions||Hibernate Interview Questions|
|JavaServer Faces (JSF) Interview Questions||Java 8 Interview Questions|
|JavaFX Interview Questions||NHibernate Interview Questions|
|Spring MVC Framework Interview Questions||The Java Debugger (JDB) Interview Questions|
|Java J2EE Technical Support Engineer Interview Questions|
Presentation Tier Design Considerations And Bad Practices
Business Tier Design Considerations And Bad Practices
J2ee Patterns Overview
Presentation Tier Patterns
Business Tier Patterns
Epilogue J2ee Patterns Applied
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