Which of the following is considered the first high-level programming language?

The correct answer is C, Dennis Ritchie. He created C at Bell Laboratories in the early 1970s and used it to rewrite the UNIX operating system, which is why C is called the mother of system programming languages and still underlies most operating systems. Option A is wrong because James Gosling developed Java at Sun Microsystems and released it in 1995, having first named it Oak. Option B is wrong because Bjarne Stroustrup extended C with classes and objects and named the result C++, so he is the creator of C++ and not of C. Option D is wrong because Guido van Rossum created Python and released the first version in 1991. Examiners set this as a match-the-pair question with all four names in one column, so learn the set together: Ritchie for C, Stroustrup for C++, Gosling for Java, van Rossum for Python, Backus for FORTRAN and Wirth for Pascal.

The correct answer is D, compile a java program. The command javac is the Java compiler: it takes a source file with the extension .java, checks its grammar and converts it into a class file containing bytecode, the intermediate code that any Java Virtual Machine can run. Option A is wrong because a compiled program is executed by the separate command java, which loads the class file into the virtual machine and starts it. Option B is wrong because debugging is done with a tool such as jdb or the debugger built into a development environment, not with javac, which only reports errors of grammar. Option C is wrong because interpretation of the bytecode is the work of the Java Virtual Machine at the time the program runs; javac finishes its work before that. Remember the two-step chain that makes Java platform independent: javac produces bytecode, and the virtual machine on each computer runs that bytecode.

The correct answer is B, interpreter. An interpreter reads one statement of the source program, translates it and executes it immediately before moving to the next, so it stops at the first error it meets and tells the programmer about that error alone; this makes it convenient for learning and for testing small pieces of code, though execution is slower because translation happens every time the program runs. Option A is wrong because a compiler translates the entire program in one pass, lists all the errors together and produces an object file that runs quickly thereafter. Option C is wrong because an assembler is a special translator that converts assembly language, a second-generation language, into machine code. Option D is wrong because a loader does no translation at all; it merely places the ready executable program into main memory so that the processor can start it. BASIC and Python are the standard examples of interpreted languages.

The correct answer is C, long double. Java has exactly eight primitive data types, namely byte, short, int, long, float, double, char and boolean, and long double is not among them; it belongs to C and C++, where it denotes an extended precision floating point number, so the option is a deliberate trap for candidates who have learnt C first. Option A is wrong as an answer because short is a genuine Java primitive, a sixteen-bit signed integer. Option B is wrong because long is also genuine, a sixty-four-bit signed integer used when int is too small. Option D is wrong because boolean is a primitive that holds only the two values true and false and is the type of every condition in Java. A useful way to hold the eight in mind is to group them: four integer types, two floating point types, one character type and one logical type.

The correct answer is B, all of the options, because each of the other three statements is a genuine rule of the language and the question asks which of them apply. Option A is a true statement and therefore not the answer by itself: reserved words such as class, int, public and static already have a meaning for the compiler and cannot be reused as identifiers. Option C is likewise true on its own: Java is case sensitive, so total, Total and TOTAL are three different variables, and a mismatch of case is one of the commonest beginner errors. Option D states the usual rule that an identifier begins with a letter, although Java also allows an underscore or a dollar sign as the first character and never allows a digit there. Since every listed statement holds good, the combined option is the one to mark; whenever three individually correct statements appear with an all of the above choice, check each and then take the combined option.