Learn Programming

When something breaks, troubleshooting the issue should be possible from only the metrics being collected. You should not be to depending on log files, or looking at code, to deal with an outage.

In a multi-server deployment, it is best practice to slowly ramp up traffic to a newly started task, giving it time to warm up, and to not harm the overall performance of the service. You may be tempted to warm up new tasks by sending it artificial traffic, before it is placed into the user-serving path. Artificial traffic can be problematic if it... See more

Looking at the worst case latency is more meaningful, and more reflective of the user perceived performance.

Integer literals are of type int unless they are suffixed with an L , denoting that they are to be produced as a long value

There are many features of the JVM that have a fixed cost per running JVM, such as JIT and garbage collection. Your application may also have fixed overheads, such as resource polling (backend database connections), etc. If you run fewer, but larger (in terms of CPU and RAM) instances, you can reduce this fixed cost, getting an economy of scale.... See more

Specific to Java, there are metrics that can be helpful to understand the health, and performance of the application. Guiding future decisions on how to scale and optimise the application. Garbage collection time, heap size, thread count, JIT time are all important and Java specific.

Collections work only with object types, so primitives must be wrapped when stored in them.