Programming Output Evaluation

new StringBuilder() creates two distinct objects, so == returns false (different references). StringBuilder does NOT override equals() - it inherits Object's default implementation which also checks reference equality. Therefore equals() returns false too, unlike String which compares content.

After s2 = s1, both variables reference the exact same StringBuilder object. The == operator returns true (same reference). StringBuilder's equals() method (inherited from Object) also returns true because it compares references, which are now identical.

The switch expression evaluates to i = 3. Since no case matches 3, the execution jumps to the default label. Because there is no break statement after the default, case 0, and case 1 statements, execution falls through all of them until a break is encountered in case 1, printing 'default', 'zero', and 'one'.

Java's char primitive type is a 16-bit unsigned integer representing UTF-16 code units, ranging from 0 (null character) to 65535 (2^16-1). Unlike other integral types (byte, short, int), char is unsigned and cannot represent negative values. Option A describes short, B describes byte, and C describes int.

Java automatically promotes the smaller primitive type to match the larger type during comparison operations. This is part of binary numeric promotion - for example, an int compared to a long is promoted to long, a float compared to a double is promoted to double. This promotion happens automatically without requiring explicit casting from the programmer.

The trimString() method calls x.trim() which removes leading/trailing whitespace. On input ' tcs ', this returns 'tcs'. The finally block always executes, so output is 's = tcs' followed by 'In finally'. No exception occurs, so flow is normal.

This code produces a compiler error because the catch block order is invalid. Exception is a superclass of NullPointerException, so catching Exception first makes the NullPointerException catch unreachable. More specific exceptions must be caught before their parent types.

The division 10 / 5 returns 2.0 (as double). Since no exception occurs, the catch block is bypassed. However, the finally block is guaranteed to execute regardless of whether an exception is thrown, appending 'In finally' to the output. Thus, the program prints both lines sequentially.

The code divides 10 by 0, throwing ArithmeticException '/ by zero'. This is caught by the Exception handler, which prints the message and calls System.exit(0). System.exit() terminates the JVM immediately, so the finally block never executes. Output is only the exception message.

Division by zero throws ArithmeticException with message '/ by zero'. The catch block prints 'Exception happened / by zero'. Control then proceeds to the finally block, which prints 'In finally'. Both statements execute in sequence.

The code has empty statements (multiple semicolons) and string literals without statements. String literals not followed by anything are valid expressions that do nothing. Line 6 and 8 are valid no-op expressions. Line 7 printf executes, printing 'Executing...'. No errors occur.

Both 6/4 expressions use integer division. In C, int/int truncates toward zero. 6/4 = 1 (integer). The printf uses %d for first (prints 1) and %f for second. %f expects a float/double but receives int 1, causing undefined behavior. The expected output shows 1 and 0.000000 for this UB.

In C, the switch statement requires an expression of integer type (int, char, enum). A float variable cannot be used as the switch expression because float values are not discrete and cannot be compared exactly for equality matching. This code will fail to compile with an error about illegal switch expression type. Options A and B would be outputs if the code compiled, but compilation never succeeds.