Lee & Nee Softwares Exports PHP Developer Interview Questions and Answers

Program to return list of .tst files in given directory and subdirectories

• Use recursion to traverse through all directories and subdirectories

• Check if each file has .tst extension and add to list if true

• Use built-in functions like os.listdir() and os.path.splitext() in Python

The '==' operator is used for comparing values of primitive data types, while the 'equals' method is used for comparing objects in Java.

• Use '==' to compare primitive data types like int, char, boolean, etc.

• Use 'equals' method to compare objects like Strings, Lists, etc.

• Example: int a = 5; int b = 5; if(a == b) { // true }

• Example: String str1 = 'hello'; String str2 = 'hello'; if(str1.equals(str2)) { // true }

Abstract classes are used to provide a common base for multiple classes, while interfaces define a contract for classes to implement.

• Abstract classes can contain both abstract and concrete methods, while interfaces can only have abstract methods.

• Abstract classes can have constructors, while interfaces cannot.

• Interfaces allow for multiple inheritance, while classes can only inherit from one abstract class.

• Abstract class...read more

Singleton design pattern ensures a class has only one instance and provides a global point of access to it.

• Ensure a private static instance variable in the class.

• Provide a public static method to access the instance, creating it if necessary.

• Use synchronized keyword or double-checked locking to make it thread-safe.

Merge sort is a divide and conquer algorithm that divides the input array into two halves, sorts each half, and then merges the sorted halves.

• Divide the array into two halves

• Recursively sort each half

• Merge the sorted halves back together