Advanced Java Interview Questions- Part 3

Answer:

A Java component’s preferred size is the minimum component size that allows the component to display normally.

Answer:

The setLayout() method is useful for specifying a container’s layout. For instance, setLayout(new FlowLayout()); will be set the layout as FlowLayout.

Answer:

The Collection API in Java is a set of classes & interfaces that support operation on the collections of objects. Those classes & interfaces are more powerful, flexible, & regular than the vectors, arrays, and hash tables, if replaced effectively.

Answer:

An Iterator interface is used as an alternative for enumerations in Java Collection. However, an Iterator differs from the enumerations in two ways:

• It allows the caller to remove the given elements from a specified collection during the element’s Iteration.
• Method names have been enhanced.

Answer:

Following are the differences between yielding & sleeping:

Answer:

No, Java garbage collection does not guarantee that a program will not run out of memory. The central objective of garbage collection is to identify & discard those objects that are no longer required by the Java program so that their resources can be reused & reclaimed. An object needs to garbage collected when it is unreachable to the Java program. If there is insufficient memory required for a new object, then the garbage collector attempts to reclaim its memory by releasing the memory used by the objects with no references. However, if there’s still insufficient memory, the program will throw an ‘out of memory’ exception.

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A package statement is confined to appear as the first line in a source code file (excluding blank comments & lines).

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No, it is impossible to invoke the finalize() method of an object while it is reachable. However, the finalize() method may get invoked by other objects.

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• Preemptive scheduling: Under this, the highest priority task gets executed until it enters the dead states or a higher priority task comes into existence.
• Time slicing: Under this, a task gets executed for a predefined slice of time, then reenters the pool of ready tasks. Thereby, the scheduler decides which task should be executed next, based on priority and various other factors.

Answer:

Clipping refers to the process of confining paint operations to a limited shape or area. When displaying a large portion of a picture, certain parts of the image are inside, while the others are partially visible. The elements or lines that are partly visible need to be omitted, so we use clipping to decide the visible-invisible portion. Thereon, the visible part is selected & the invisible part is discarded.

Answer:

A native method is a method whose implementation is written in other languages such as C++ & C. The ‘native’ keyword is used before a method indicates that it is implemented in another language.

Answer:

Yes, the “for statement” can loop indefinitely.

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The order of precedence in Java determines the order of evaluating the operators in expressions. The order of associativity determines the evaluation of operators with the same precedence.

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A task’s priority in Java is an integer value that determines the relative order, wherein it needs to executed with respect to other tasks. The scheduler first schedules higher priority tasks & later schedules lower priority tasks.

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The java.awt.AWTEvent class is the top class in the AWT event hierarchy.

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The initial state of a thread is the “Ready” state after it has been started & created; that stage signifies the thread is ready for task execution; thereon, it can be running.

Answer:

The central purpose of finalization is to allow an unreachable object to perform a cleanup processing before the object’s garbage collection.

Answer:

Both the “&” and “&&” operators are used to evaluate the conditional statements. The & operator is a bitwise operator, while && is a logical operator. The fundamental difference between the & and the && operator is that the former evaluates both sides of the expression. On the other hand, the latter evaluates only the left side of the expression to acquire final results.

Answer:

Gregorian Calendar class provides an implementation of the abstract Calendar class. It renders us multiple methods to access & manipulate the current minute, second, hour, day of the week, week of the year, etc.

Answer:

validate() method causes a container to be laid out & redisplayed in Java.