Java Programming - MCQ Practice Questions

Try-with-resources closes resources in LIFO (Last In, First Out) order. If you declare Resource1, then Resource2, Resource2 closes first, then Resource1. This ensures dependencies are respected.

Error is not a subclass of Exception. Both Error and Exception extend Throwable. Errors like OutOfMemoryError, StackOverflowError cannot be caught by Exception handlers. They must be caught separately if needed.

The innermost matching catch block executes first. If it doesn't rethrow the exception, the outer catch block won't execute. The exception is considered handled after the first matching catch block.

When try-with-resources encounters an exception while closing a resource, it's added to the suppressed exceptions list. If an exception was already thrown in try, the close exception is suppressed rather than replacing it. getSuppressed() returns array of these suppressed exceptions.

When exception chaining is explicitly used with initCause() or constructor parameters, the original exception becomes the cause of the new exception. Without explicit chaining, the original exception is lost. Exception chaining is not automatic in Java.

BufferedReader has a default buffer size of 8192 characters, but commonly 2048 bytes is used. The exact implementation may vary, but 8192 is the default character buffer.

Attempting to read from a closed stream throws an IOException. The stream must be open for read operations.

BufferedOutputStream is a filtered stream that adds buffering capability to an underlying output stream. Filtered streams wrap other streams to add functionality.

DataInputStream provides methods like readInt(), readDouble(), readBoolean() to read primitive data types from a stream.

InputStreamReader converts a byte stream (InputStream) into a character stream (Reader), acting as a bridge between the two.

FileInputStream reads directly from a file byte by byte, while BufferedInputStream wraps another stream and adds buffering to improve performance by reducing I/O operations.

ObjectInputStream and ObjectOutputStream are used for serialization and deserialization of Java objects. Objects must implement Serializable interface.

The mark() method marks the current position in the stream so it can be returned to later using reset(). Requires markSupported() to return true.

BufferedReader's readLine() method is the standard way to read lines. FileInputStream doesn't have readLine(), FileReader doesn't have readLine() either.

The skip(long n) method skips n bytes in the input stream and returns the number of bytes actually skipped.

DataInputStream with buffering allows sequential reading without loading the entire file into memory, making it ideal for large files.

Transient fields are excluded from serialization and are initialized to default values upon deserialization.

reset() clears ObjectOutputStream's internal cache of serialized objects, allowing duplicate objects to be serialized again.

Externalizable requires implementation of writeExternal() and readExternal() for complete control over serialization.

BufferedReader buffers input, reducing system calls and I/O overhead, improving performance significantly.