Java is one of the powerful general-purpose programming languages, created in 1995 by Sun Microsystems (now owned by Oracle). Java is Object-Oriented. However, it is not considered as pure object-oriented as it provides support for primitive data types (like int, char, etc). Java syntax is similar to C/C++. 

But Java does not provide low-level programming functionalities like pointers. Also, Java code is always written in the form of classes and objects. Android heavily relies on the Java programming language all the SDKs required to build for android applications use the standard libraries of Java. 

If one is coming from a traditional programming background like C, C++, Java is easy to learn. So in this discussion, there is a complete guide to learn Java specifically considering Android App Development.

Introduction to Java for Android Development  : https://www.geeksforgeeks.org/learn-java-for-android-app-development-a-complete-guide/