Zypp Electric Android Developer Interview Questions, Process, and Tips

Swap two numbers without using a third variable

• Use bitwise XOR operation to swap two numbers without using a third variable

• Example: a = 5, b = 10. a = a XOR b, b = a XOR b, a = a XOR b. After swapping, a = 10, b = 5

There are four types of inheritance in Java: single, multilevel, hierarchical, and multiple.

• Single inheritance: a class can only inherit from one superclass.

• Multilevel inheritance: a class can inherit from a class which is also derived from another class.

• Hierarchical inheritance: multiple classes inherit from a single superclass.

• Multiple inheritance: a class can inherit from multiple superclasses (not supported in Java

A singleton class in Java is a class that allows only one instance of itself to be created and provides a global point of access to that instance.

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

• The constructor of a singleton class is private to prevent instantiation from outside the class.

• The getInstance() method is used to access the single instance of the class...read more

Constraint layout is more flexible and efficient than relative layout.

• Constraint layout allows for complex layouts with fewer nested views.

• It uses constraints to position and size views relative to other views or parent layout.

• Relative layout positions views relative to each other or parent layout using attributes like 'above', 'below', etc.

• Constraint layout is recommended for complex layouts with many views.

• Relative l...read more

To find a missing element in an array, iterate through the array and compare each element with a range of expected values.

• Sort the array if it is unsorted.

• Iterate through the array and compare each element with a range of expected values.

• If an element is missing, return it.

• If no element is missing, return null or -1.