Java9 on Micha Kops' Tech Notes

Analyzing Java Problems – Tools, Snippets and Workflows

Mon, 30 Apr 2018 00:00:00 +0200

When we need to investigate the cause for a dysfunctional Java application we have a plethora of tools available that on the one hand help us in gathering information, artifacts and statistics and on the other hand help us in processing this information and identifying possible problems.

The following list of tools, snippets, workflows and information about specific artifacts could provide a starting point for analyzing such problems and covers topics like heap-dumps, thread-dumps, heap-histograms, heap-regions, garbage-collection-logs, hotspot-compiler/codecache-logs, debugging native-memory, tools for heap-dump-analysis, JVM unified logging and more..

Reactive Streams – Java 9 Flow API, RxJava, Akka and Reactor Examples

Sun, 14 Jan 2018 00:00:00 +0100

Reactive Streams is an initiative trying to standardize asynchronous stream processing with non-blocking back-pressure. With Java 9, new classes in the java.util.concurrent.flow package offer a semantically equivalent counterpart to this standard that may be adopted by other frameworks.

In the following short tutorial we’re implementing examples for reactive streams with Java 9 and the Flow API, with RxJava2, with Akka, with Reactor and finally there is an example in RxJava1, too though it does not follow the standard.

Snippet: Java 9 Modules and JPMS

Mon, 17 Apr 2017 00:00:00 +0200

Playing around with the new module system in Java 9 I simply wanted to write down how to achieve the most basic tasks.

Therefore I created the following module how-to based upon a simple demonstration project consisting of two dependant modules.

Figure 1. Modules Component-Diagram

Prerequisites and Setup

We need an early access build of the Java ™ 9 JDK, available for download here.

In addition we should make sure, that our environment variable JAVA_HOME is set to the corresponding directory and calling java -version returns something similar to this: