What is Performance Testing?

Performance testing is the general name for tests that check how the system behaves and performs. Performance testing examines responsiveness, stability, scalability, reliability, speed and resource usage of your software and infrastructure. Different types of performance tests provide you with different data, as we will further detail.

Before performance testing, it’s important to determine your system’s business goals, so you can tell if your system behaves satisfactorily or not according to your customers’ needs.

After running performance tests, you can analyze different KPI's, such as the number of virtual users, hits per second, errors per second, response time, latency and bytes per second (throughput), as well as the correlations between them. Through the reports you can identify bottlenecks, bugs and errors, an decide what needs to be done.

When should you use Performance Testing?

When you want to check your website performance and app performance, as well as servers, databases, networks, etc. If you work with the waterfall methodology, then at least each time you release a version. If you’re shifting left and going agile, you should test continuously.

What is Load Testing?

Load testing is testing that checks how systems function under a heavy number of concurrent virtual users performing transactions over a certain period of time. Or in other words, how systems handle heavy load volumes.

When should you use Load Testing?

When you want to determine how many users your system can handle. You can determine different user scenarios that let you focus on different parts of your system, like the checkout webpage on your website or app for web load testing. You can also determine how the load behaves, like the geo-location users come from or how the load builds and sustains in the system. Basically, load testing is something you should do all the time, to ensure your system is always on point. 

What is Stress Testing?

Stress testing is testing that checks the upper limits of your system by testing it under extreme loads. The testing examines how the system behaves under intense loads, and how it recovers when going back to normal usage, i.e are the KPIs like throughput and response time the same as before? In addition to load testing KPIs, stress testing also examines memory leaks, slowness, security issues and data corruption.

Stress testing can be conducted through load testing tools, by defining a test case with a very high number of concurrent virtual users. If your stress test includes a sudden ramp-up in the number of virtual users, it is called a Spike Test. If you stress test for a long period of time to check the system’s sustainability over time with a slow ramp-up, it’s called a Soak Test.

When Should You Use Stress Testing?

Website stress tests and app stress tests are important before major events, like Amazon great India sale with high demand or the elections. But we recommend you stress test every once in a while so you know your system’s endurance capabilities. This ensures you’re always prepared for unexpected traffic spikes, and gives you more time and resources to fix your bottlenecks.

Identify the sections of corejava, you should be knowing for android development and it really depends on what are you implementing in android. I would suggest you to know about

1. collections

2. java.awt

3. java.io, if you are operating on storage

4. java.net or third party framework if your application makes webservice calls.

In addition, there is lot to learn in android itself, if you are new to android development.