Java Programming

nAbility to tackle challenging problems

nImproved communication between users, analysts, designers, and programmers

nIncreased consistency in analysis, design, and programming

nExplicit representation of commonality among system components

nSystem robustness

nReusability of analysis, design, and programming results

while loop and for loop are entry controlled loops as they check looping condition at the entry point.

do while loop is exit controlled loop as it checks looping condition at exit point.

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There is no such thing as 'the general syntax of a default constructor'. A default constructor is one that is generated by the compiler if you don't specify any constructors at all. Semantically speaking, it is public and takes no arguments, but this is not 'syntax'.

The term upcall is typically used in the context of using a framework, such as CORBA. When a request is sent from a client application to a server application, the framework is responsible for data marshalling, data transmission, and notification of the recipient that a request has been issued. An upcall is the call into the user code from the framework. This is typically supported through the use of a registered callback function registered either directly by the user, or indirectly through the mechanisms of the framework. An upcall is also called a callback.

The role of a technical support engineer is to plan analyze the program of the each profile plan, as per standard engineering requirements, specification of the project.

An abstract class cannot have a constructor and hence you cannot invoke the constructor of the class - i.e., you can instantiate an abstract class and hence you cannot call the constructor of an abstract class.

The Finally block in java is used along with the try-catch statements.

The usual structure is

try {

.....

} catch(Exception e){

....

} finally {

.....

}

In the finally block we usually have code that is used to perform clean up activities corresponding to the code in the try block. When an exception occurs in the try block control comes to the catch block and the rest of the code in the try block would not execute. In such cases we may need to have some code that cleans up the objects that we created/used in the try block.

No matter what happens, the code inside the finally block would definitely execute.

The best use of finally block is when we are connecting to the database. In the try block we would have the statements that instantiate the connection, prepared statement, result set etc. If the query fails then all these objects would be left open and the code would continue. So in the finally block we usually nullify these statements so that even in case of an error the unused objects are cleared.

Example:

Connection con;

PreparedStatment PS;

ResultSet rs;

try{

con = ConnectionManager.getConnection();

PS = con.prepareStatement(query);

rs = PS.executyQuery();

......

} catch (Exception e){

e.printStackTrace();

} finally {

con.close();

PS.close();

}

In case of an error the connection & prepared statement objects would remain open if we do not have the finally block.

Tip: Whatever code we have inside the finally block would be run definitely if the try block is invoked. We can even use the finally block to check if the try block was reached and executed. If the try executes then we can rest assured that the finally would also get executed.

It is an binary arithmetic operator which returns the remainder of division operation. It can used in both floating-point values and integer values.

opLeft % opRight where, opLeft is the left operand and opRight is the right operand. This expression is equivalent to the expression opLeft - ((int) (opLeft / opRight) * opRight)

not exactly..... only If your class is public then the java program name should be the public class name with extension Sample.java >> public class Sample { public static void main(String[] args) { ..... } } NonPublicClass.java class SomeOtherName { ......... }

1. Testability/Increased Quality (automated testing can increase speed of testing and increase quality) 2. Code re-use (Polymorphism, Generics, Interfaces) 3. Code extensibility 4. Catch errors at compile time rather than at runtime. 5. Maintainability: If designed correctly, any tier of the application can be replaced by another that implements the correct interface(s), and the application will still work (can use multiple user interfaces, can swap out data providers, etc.). 6. Reduces large problems to smaller, more manageable ones. 7. Fits the way the real world works. It is easy to map a real world problem to a solution in OO code.

Galaxies because the sun is a star.

The decision tree is a classification model, applied to existing data. If you apply it to new data, for which the class is unknown, you also get a prediction of the class. The assumption is that the new data comes from the similar distribution as the data you used to build your decision tree. In many cases this is a correct assumption and that is why you can use the decision tree for building a predictive model.

Wrapper classes are classes that are used to make primitive variables into objects, and to make wrapped objects into primitives. int, boolean, double are all primitive data types and their respective wrapper classes are Integer, Boolean, and Double. Wrapper classes are useful in storing primitive data types in higher level data structures such as Stack<Object>, List<Object>, Queue<Object>, since primitives cannot be directly placed in these data structures they must be boxed in the wrapper classes. But, here's the good news, with the new Java 5.0, there is no need no worry about wrapper classes and boxing and unboxing (unless it's something taught in class), since there is auto-boxing and unboxing, therefore, one can directly "add" primitives to a data structure and let the JVM do the rest.

High level programming is drag & drop, easy peasy programming. In the objects you use to create something ( program, graphics). The components are made up of middle level programming. A language that is easier to remember than zeros & one's...which is a low-level language that integrated chips use to work.

A primitive variable can be one of eight types: char, boolean, byte, short, int, long, double, or float. Once a primitive has been declared, its primitive type can never change, although in most cases its value can change. they are used to store values like name, age, salary etc.

You can not overwrite a static method in Java,and 'main' is a static method.so,you can't overwrite the 'main'.

Core java refers to the core or basic concepts of the Java programming language. Things like encapsulation, inheritance, multi-threading, exception handling and other basic feature of java that comes as part of the Java standard edition forms Core Java

import PackageName.SubPackage.ClassName.SubClass;

or

import PackageName.SubPackage.*; \\ this will import any class in the package

note : it's very simple, consider the packages are like folders, as the are.

This can be a confusing topic because one can argue that sharing method attributes between a super or abstract class with a derived class could be described by either Polymorphism or Inheritance. One significant differerence could be illustrated as to when or under what circumstances you would you use one or the other. An ideal instance of using Inheritance would be when you want to create an entirely new class, but wish to borrow a group of existing attributes or methods resident in an existing Abstract or super Class, instead of re-inventing the wheel. If you had an Abstract Class Carnivore and wanted to create a subclass Cat, you could instantly inherit all the methods that were common in Carnivore that applied to Cat without writing new code. Polymorphism could be best applied when you had an existing SubClass that you wanted to modify or add a feature that could borrow a method that existed in a higher class. Take the Cat subclass, which inherited attributes from Carnivore, and you wanted to add the method Stalk, which would generically describe how a carnivore approaches its prey. However its implementation in Cat would detail the stealth it uses that are unique to a Cat.

45,60,70,13,10,30,22,33,24construct avl tree

Access control list (ACL)