What is memory Leaks in Android development ?

The application creates objects, they lie in memory and can not clean out after the completion of its work.

Why is this happening ?

Java has its own means of clearing memory from unused items. This is garbage collection .

The garbage collector marks all objects that can be deleted if they are not referenced. Memory leak - this is just a lost reference, which shows that the object can not be deleted.

The complexity of this bug is that until a certain time it is not visible and it can not interfere.
There's a good quote from Benjamin Franklin: “A small leak will sink a great ship."
Memory leaks take the RAM of the application. The amount of raw memory will grow and may one day cause your app to slow down and crash . This will lead to user dissatisfaction and most likely the app will be removed...

I propose to consider several ways to synchronize threads and processes that are most commonly used in Java. They differ in implementation and use cases. We will consider all methods on interesting examples.

Critical section

This method is suitable for you if:

• parallel threads work with a shared resource;
• requires synchronization between threads, not processes;

This method of synchronization is called resource synchronization ("open – close" synchronization). The idea of this method is that each object in Java has an associated monitor . A monitor is a kind of tool to control access to an object.

Example of the design pattern An object pool in the Java programming language.

In class-based programming, the factory method pattern is a creational pattern that uses factory methods to deal with the problem of creating objects without having to specify the exact class of the object that will be created. This is done by creating objects by calling a factory method—either specified in an interface and implemented by child classes, or implemented in a base class and optionally overridden by derived classes—rather than by calling a constructor.

Example of "Builder" design pattern in Java

Abstract Factory classes are often implemented with Factory Methods, but they can also be implemented using Prototype. Abstract Factory might store a set of Prototypes from which to clone and return product objects.

• Factory Method: creation through inheritance.
• Prototype: creation through delegation.
• Virtual constructor: defer choice of object to create until run-time.

Sometimes there is a problem to find the minimum path from point A to point B . The map can have barriers and be like a labyrinth. Similar tasks can be done in game development, PCB design and GPS development, etc.

There is a large set of algorithms for finding the minimum path. The most simple and effective is the Wave trace Algorithm (Lee algorithm). Which is based on the methods of breadth-first search.

This algorithm is not difficult to understand. It will be understandable even for a beginner in programming.