Java Programming Fundamentals

The finalize() method is intended as a finalization hook for releasing system resources (file handles, network connections, native memory) before an object is garbage collected. However, it's deprecated since Java 9 due to unreliability - better to use explicit resource management or try-with-resources. The statement is technically true about its purpose. Note: This is a duplicate of 141360.

Local variables have block scope in most languages (Java, C, C++). If two blocks are disjoint (not nested), they can each declare variables with the same name without conflict. Each variable is only visible within its own block. This is valid and commonly used.

All loop constructs (for, while, do-while) are fundamentally controlled by boolean expressions that determine when the loop continues or terminates. Even for loops with counters implicitly use a boolean condition. This is a fundamental control flow principle in programming.

Switch statements can be nested within each other - a case or default clause in one switch can contain another complete switch statement. This is allowed in C, C++, Java, and similar languages. Each switch operates on its own expression independently.

PreparedStatement is the standard JDBC class that supports parameter placeholders ( ? ) and lets you set values before execution. CallableStatement is used for stored procedures, which also accept parameters, but the question asks for a type that can execute parameterized queries, and the only universally correct choice listed is PreparedStatement. The other options refer to non‑existent classes, so the stored answer is right.

Methods in a class can share the same name through method overloading, as long as they have different parameter lists (signatures). The compiler distinguishes them by the number, types, and order of parameters. The statement is false because method overloading is a fundamental feature of object-oriented programming.

Constructors are special methods that initialize objects and never have a return type, not even void. They must have the same name as their class and are automatically called when an object is created using the new keyword. The presence of any return type (including void) would make it a regular method, not a constructor.

The Runnable interface requires only the run() method to be implemented. The start() method belongs to the Thread class, not Runnable. When implementing Runnable, you override run() with your task logic, then pass the Runnable to a Thread which calls start() to invoke run() in a new thread.

The wait() method explicitly releases the object lock before putting the thread to wait. The thread must wait for another thread to call notify() or notifyAll() on the same object, then reacquire the lock before resuming execution. This mechanism enables inter-thread communication by allowing other threads to access the synchronized object while one thread waits.

When notifyAll() awakens waiting threads, the JVM does not guarantee any ordering; threads compete for the monitor and any of them may proceed first. Hence the correct answer is that you can never be sure which thread runs first, matching the marked option.

Thread constructors accept either a Runnable object (for the task to execute), a ThreadGroup, a name string, or combinations thereof. Option A is invalid because Thread doesn't accept a plain Object parameter. Option E is invalid because Object doesn't implement Runnable. Options B (String name), C (Runnable target), and D (ThreadGroup + Runnable + name) match valid Thread constructor signatures in Java.

Point is a static nested class inside Line. To call getPoint() (an instance method), you need a Line instance: (new Line()).getPoint(). Since Point is defined inside Line, the full type is Line.Point. Option D correctly combines both: Line.Point p = (new Line()).getPoint(). Options A and C miss the Line. prefix for the nested class type. Option B is missing the Line instance.

Running with -ea enables assertions. If no arguments are passed (length 0) or more than one argument is passed (length 2 or more), the assertion a.length == 1 fails, raising an AssertionError.

Throwing IllegalArgumentException is the standard practice in Java to signal that a method argument is invalid (null) when it is required to be non-null.

The method count recursively calls itself with ++i without any base case or termination condition, leading to infinite recursion. This rapidly exhausts the execution stack and throws a java.lang.StackOverflowError.

Calling s.defaultWriteObject() is the standard Java serialization approach to write the default serializable fields of the class to the stream, maintaining serialization compatibility.

An abstract class is declared using the abstract modifier. It can have concrete methods with a body {}. Option 2 has a valid abstract class containing a concrete method. Option 1 fails because the method has no body and is not marked abstract. Options 3 and 4 have syntax errors.

In Java, the extends keyword is used for inheritance between the same kinds of types: a class can extend another class, and an interface can extend another interface. A class implements an interface using the implements keyword.

JavaBeans naming convention requires getters to use 'get' prefix (or 'is' for boolean properties) and setters to use 'set' prefix. getCust() correctly uses the 'get' prefix for a getter method. isColorado() correctly uses the 'is' prefix for a boolean getter. addSize(), deleteRep(), and putDimensions() don't follow JavaBeans patterns.