Java and Perl Programming Concepts Quiz

Setting $#a = 0 truncates the array to only its first element (index 0), removing all other elements. The array @a now contains only one element (0). When an array is assigned to a scalar in Perl, it returns the number of elements in the array, so $size = 1.

The split() function with no arguments splits the default variable $_ on whitespace. Whitespace includes spaces, tabs, and newlines, and leading/trailing whitespace is ignored. The string ' a b c ' splits into three non-whitespace elements: 'a', 'b', and 'c'.

In Perl, the bareword construction NEW A acts as a method call A->NEW(). Inside AUTOLOAD, calling ref(shift) prints the reference package name A twice: first for the invalid method call foo(), and a second time when the object goes out of scope and triggers the DESTROY method.

The == operator performs numeric comparison in Perl, converting strings to numbers. Both '123' and '0123' convert to the number 123 (leading zeros are ignored in numeric conversion). Therefore, $a == $b evaluates to true, printing 'same'.

A quantifier in regular expressions specifies how many times the preceding character or group must match. Common quantifiers include * (0 or more), + (1 or more), ? (0 or 1), and {n,m} (n to m times). This is the standard definition in regex syntax.

The stat() function in Perl returns a 13-element list containing file information, including the inode number (index 1) and last access time (index 8). Both values are part of the returned array, making 'Both of the above' the correct answer.

Perl uses the spaceship operator <=> inside a block to perform numerical comparisons for sorting, using the special package variables $a and $b. The default sort function performs ASCII-alphabetical sorting, while using $1 and $2 or $_[0] and $_[1] inside the sort block is syntactically incorrect.

@a contains two array references: [1,2,3,4] at index 0 and [5,6,7,8] at index 1. @{$a[1]} dereferences the second array, giving (5,6,7,8). The slice [1..3] selects elements at indices 1, 2, and 3, which are 6, 7, and 8. Join with spaces gives '6 7 8'.

A->new('foo') passes 'A' as $class and 'foo' as $param (correct). new A('foo') also passes 'A' as $class and 'foo' as $param (correct). However, A::new('A', 'foo') is NOT equivalent - it bypasses Perl's inheritance mechanism and directly calls the subroutine, which fails if new() is inherited from a parent class. The third form is methodologically different.

The pattern <.*> matches any text enclosed in angle brackets. The * quantifier is greedy by default, matching as much as possible. For nested tags like , <.*> matches from the first < to the last >, removing all content between. Option D is the correct greedy regex that deletes all HTML tags.

In Java Collections Framework, SortedMap is an interface that extends Map. It provides a total ordering on its keys. Classes like TreeMap implement this interface. Abstract classes and concrete classes exist, but SortedMap itself is an interface.

SortedSet is an interface in Java. ConcurrentSkipListSet is a concrete class that implements the SortedSet interface, providing a thread-safe sorted set implementation based on a skip list data structure. HashMap and Queue are unrelated to SortedSet implementation.

The RandomAccess interface is part of the java.util package in Java Collections Framework. It's a marker interface used by List implementations to indicate that they support fast (generally constant time) random access to elements, like ArrayList.

Compile-time errors (checked exceptions) must be handled at compile time through declaration or catching. They cannot be handled with try-catch at runtime because the compiler enforces their handling before the code can run. Throwable is the superclass of all errors and exceptions but doesn't apply here.