May 11, 2019

Srikaanth

Pegasystems Advanced Java Interview Questions Answers

What Is The Role Of The Jms Provider?

The JMS provider handles security of the messages, data conversion and the client triggering. The JMS provider specifies the level of encryption and the security level of the message, the best data type for the non-JMS client.

What Is The Difference Between Byte Message And Stream Message?

Bytes Message stores data in bytes. Thus the message is one contiguous stream of bytes. While the Stream Message maintains a boundary between the different data types stored because it also stores the type information along with the value of the primitive being stored. Bytes Message allows data to be read using any type. Thus even if your payload contains a long value, you can invoke a method to read a short and it will return you something. It will not give you a semantically correct data but the call will succeed in reading the first two bytes of data. This is strictly prohibited in the Stream Message. It maintains the type information of the data being stored and enforces strict conversion rules on the data being read.

What Is Byte Message ?

Byte Messages contains a Stream of uninterrupted bytes. Byte Message contains an array of primitive bytes in it's payload. Thus it can be used for transfer of data between two applications in their native format which may not be compatible with other Message types. It is also be useful where JMS is used purely as a transport between two systems and the message payload is opaque to the JMS client.

What Is Object Message ?

Object message contains a group of serializeable java object. So it allows exchange of Java objects between applications. sot both the applications must be Java applications.

Can An Unreachable Object Become Reachable Again?

An unreachable object may become reachable again. This can happen when the object's finalize() method is invoked and the object performs an operation which causes it to become accessible to reachable objects.

When Is An Object Subject To Garbage Collection?

An object is subject to garbage collection when it becomes unreachable to the program in which it is used.

What Method Must Be Implemented By All Threads?

All tasks must implement the run() method, whether they are a subclass of Thread or implement the Runnable interface.

What Methods Are Used To Get And Set The Text Label Displayed By A Button Object?

getLabel() and setLabel().

Which Component Subclass Is Used For Drawing And Painting?

Canvas.
Pegasystems Most Frequently Asked Latest Advanced Java Interview Questions Answers
Pegasystems Most Frequently Asked Latest Advanced Java Interview Questions Answers

What Are Synchronized Methods And Synchronized Statements?

Synchronized methods are methods that are used to control access to an object. A thread only executes a synchronized method after it has acquired the lock for the method's object or class.

Synchronized statements are similar to synchronized methods. A synchronized statement can only be executed after a thread has acquired the lock for the object or class referenced in the synchronized statement.

What Are The Two Basic Ways In Which Classes That Can Be Run As Threads May Be Defined?

A thread class may be declared as a subclass of Thread, or it may implement the Runnable interface.

What Are The Problems Faced By Java Programmers Who Don't Use Layout Managers?

Without layout managers, Java programmers are faced with determining how their GUI will be displayed across multiple windowing systems and finding a common sizing and positioning that will work within the constraints imposed by each windowing system.

What's Java Swing?

Swing is basscially a type of Toolkit which is GUI toolkit for Java. It is one part of the Java Foundation Classes (JFC). Swing includes graphical user interface (GUI) widgets such as text boxes, buttons, split-panes, and tables.
Swing widgets provide more sophisticated GUI components than the earlier Abstract Window Toolkit. Since they are written in pure Java, they run the same on all platforms, unlike the AWT which is tied to the underlying platform's windowing system. Swing supports pluggable look and feel � not by using the native platform's facilities, but by roughly emulating them. This means you can get any supported look and feel on any platform. The disadvantage of lightweight components is slower execution. The advantage is uniform behavior on all platforms.

What Is Jfc?

JFC stands for Java Foundation Classes. The Java Foundation Classes (JFC) are a set of Java class libraries provided as part of Java 2 Platform, Standard Edition (J2SE) to support building graphics user interface (GUI) and graphics functionality for client applications that will run on popular platforms such as Microsoft Windows, Linux, and Mac OSX

What Is Awt?

AWT is bassically stands for Abstract Window Toolkit. AWT enables programmers to develop Java applications with GUI components, such as windows, and buttons. The Java Virtual Machine (JVM) is responsible for translating the AWT calls into the appropriate calls to the host operating system.

What Are The Differences Between Swing And Awt?

Many diff are there

> AWT is heavy-weight components, but Swing is light-weight components.
> AWT is OS dependent because it uses native components, But Swing components are OS independent.
> We can change the look and feel in Swing which is not possible in AWT.
> Swing takes less memory compared to AWT.
> For drawing AWT uses screen rendering where Swing uses double buffering.

What Are Heavy Weight Components ?

A Heavyweight component is bassically associated with its own native screen resource which is generally known as a peer.

What Is Lightweight Component?

A Lightweight component is the bassically one that "borrows" the screen resource of an ancestor , which means it has no native resource of its own -- so it's "lighter".

What Is Double Buffering ?

Double buffering is bassically the process of use of two buffers rather than one to temporarily hold data being moved to and from an I/O device. Double buffering increases data transfer speed because one buffer can be filled while the other is being emptied.

What Is An Event In Swing?

Event is basscially as Changing the state of an object is called an event.

What Is An Event Handler In Swing?

An Event handler is bassically a part of a computer program created to tell the program how to act in response to a specific event.

Give Us The Name Of The List Layoutmanagers In Java?

List is here
> Flow Layout Manager
> Grid Layout Manager
> Box Layout Manager
> Border Layout Manager
> Card Layout Manager
> GridBag Layout Manager.

Difference B/w Paint() And Paintcomponent()?

The Key point is that the paint() method invokes three methods in the following order
> PaintComponent()
> paintBorder()
> paintChildren()

As a general rule, in Swing, we should be overriding the paintComponent method unless we know what we are doing paintComponent() paints only component (panel) but paint() paints component and all its children.

What Is The Relationship B/w The Canvas Class And The Graphics Class?

A Canvas object provides access to a graphics object via its paint() method.

When Should The Method Invokelater() Be Used?

This method is used to ensure that Swing components are updated through the event-dispatching thread.

What Is A Convertor?

Converter is bassically an application that converts distance measurements between metric and U.S units.

What Is The Difference Between Jfc & Wfc?

JFC supports robust and portable user interfaces. The Swing classes are robust, compatible with AWT, and provide you with a great deal of control over a user interface. Since source code is available, it is relatively easy to extend the JFC to do exactly what you need it to do. But the number of third-party controls written for Swing is still relatively small.
WFC runs only on the Windows (32-bit) user interface, and uses Microsoft extensions to Java for event handling and ActiveX integration. Because ActiveX components are available to WFC programs, there are theoretically more controls available for WFC than for JFC. In practice, however, most ActiveX vendors do not actively support WFC, so the number of controls available for WFC is probably smaller than for JFC. The WFC programming model is closely aligned with the Windows platform.

What Is Struts?

Struts is a web page development framework and an open source software that helps developers build web applications quickly and easily. Struts combines Java Servlets, Java Server Pages, custom tags, and message resources into a unified framework. It is a cooperative, synergistic platform, suitable for development teams, independent developers, and everyone between.

How Is The Mvc Design Pattern Used In Struts Framework?

In the MVC design pattern, application flow is mediated by a central Controller. The Controller delegates requests to an appropriate handler. The handlers are tied to a Model, and each handler acts as an adapter between the request and the Model. The Model represents, or encapsulates, an application's business logic or state. Control is usually then forwarded back through the Controller to the appropriate View. The forwarding can be determined by consulting a set of mappings, usually loaded from a database or configuration file. This provides a loose coupling between the View and Model, which can make an application significantly easier to create and maintain. Controller--Servlet controller which supplied by Struts itself; View --- what you can see on the screen, a JSP page and presentation components; Model --- System state and a business logic JavaBeans.

Who Makes The Struts?

Struts is hosted by the Apache Software Foundation(ASF) as part of its Jakarta project, like Tomcat, Ant and Velocity.

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