Introduction to Java & BlueJ Environment

Q. The two types of Java programs/applications are? [2007]

Ans: The two types of Java Applications are 'Internet Applets' and 'Stand alone application'.

Q. State the distinguishing features of Java and C++?

Ans: (i) Java does not support operator overloading.(ii) Java does not use pointers.(iii) There are no header files in Java.(iv) Java does not have template classes as in C++.

Q. State the differences between Syntax errors and Logical errors.

Ans: The compiler can only translate a program if the program is syntactically correct; otherwise the compilation fails and you will not be able to run your program. Syntax refers to the structure of your program and the rules about that structure.The second type of error is a run-time error, so-called because the error does not appear until you run the program. In Java, run-time errors occur when the interpreter is running the byte code and something goes wrong.

Q. "Object is an instance of a class", explain [2010]

Ans: Object of a class contains data and functions provided in a class. it possesses all the features of a class. Hence object is termed as instance of a class.

Q. Name four basic features of JAVA.

Ans: Basic features of Java as follows:i) It is an object oriented language.ii) Java program is both compiled and interpreted..iii) Java program can be application or applet.iv) java is case sensitive language, i.e. it distinguished upper and lower case letters.

Q. Differentiate between Compiler and Interpreter.

Ans: Compiler convert source code to machine language whole at a time. Interpreter converts program from high level language to machine level language line by line or statement by statement.

Q. Java uses compiler as well as interpreter, explain.

Ans: Java compiler converts Java source code to byte code. This byte code is further converted into machine code to make it applicable for the specific platform by using interpreter.

Q. Differentiate between Source code and Byte code.

Ans: Source code is the program developed in Java Language, which is input to a computer through the keyboard. Compiler converts source code to byte code for interpretation.

Q. Differentiate between Testing and Debugging.

Ans: Testing is the process of checking program logic manually to ensure whether it contains any error or not. Debugging is the process of removing errors from a program.