1Z0-811 Flashcards — Free Oracle Java Foundations 1Z0-811 Study Cards

Exception handling

Option A is correct because exception handling in Java allows the developer to catch runtime failures (e.g., SQLException, IOException) within a try block and, in the catch block, invoke a rollback on the transaction (e.g., Connection.rollback()). If all steps succeed, the transaction is committed via Connection.commit(). This ensures atomicity — the 'all-or-nothing' property required for transaction processing.

5

The expression `x++` is a post-increment operator, which returns the current value of `x` (5) before incrementing it. Therefore, `System.out.println(x++)` prints 5, and then `x` becomes 6. Option B is correct because the output is the original value of `x`.

2.0

Option A is correct because in Java, when both operands of the division operator are integers (int), integer division is performed, which truncates the fractional part. Here, x / y evaluates to 5 / 2 = 2 (integer division), and then the int value 2 is implicitly widened to double 2.0 when assigned to the double variable result.

for(int i=0; i<arr.length; i++) { sum += arr[i]; if(sum > 100) break; }

Option B is correct because it uses a for loop with an index variable to iterate over the array, and includes an if statement with a break to exit the loop early when the sum exceeds 100. This ensures all elements are summed until the condition is met, and the loop stops immediately, preventing unnecessary iterations.

int result = sumArray(new int[]{1,2,3});

Option A is correct because it uses the correct syntax for creating and passing an anonymous int array to the sumArray method. The expression `new int[]{1,2,3}` creates an int array object with the specified elements, which matches the method's parameter type `int[]`. The method then returns the sum, which is assigned to the int variable `result`.

Car moves

Option D is correct because Java uses dynamic method dispatch (runtime polymorphism). Even though the reference variable is of type 'Vehicle', the actual object is a 'Car' instance. At runtime, the JVM calls the overridden 'move()' method of the 'Car' class, printing 'Car moves'.

FileNotFoundException

Option B is correct because `FileNotFoundException` is a checked exception that specifically indicates a file cannot be found at the specified path. The method must declare it in its `throws` clause to notify the caller that this condition can occur and must be handled or re-declared, as required by Java's checked exception rules.