Java Magazine, Sept/Oct 2017

ORACLE COM JAVAMAGAZINE SEPTEMBER OCTOBER 2017 11 java books code examples in my browser than on my tablet this is an important limitation The other is the timing of the book This volume is strictly about Java 8 but it went to press just weeks before the release of Java 9 a rather unfortunate choice that makes the contents immediately out of date Talking about completable futures if this book were to add coverage of Java 9 I would easily recommend it if youre comfortable with the caveats above Andrew Binstock MURACHS JAVA PROGRAMMING 5TH EDITION By Joel Murach The Murach books take a unique approach to teaching code language topics are presented for the most part as two page spreads The left page explains the topic while the right page provides a full working program that illustrates the details This codeintensive approach makes the work both an excellent tutorial and a book of recipes Want to connect to a database via JDBC Turn to that section and youll find multiple short programs that show you how to set up a connection formulate a query get your results and do updates By providing complete examples one of beginners most frequent problems is eliminated the question how do I use the code that I think I now understand For instructors these books have a special appeal Each two page lesson and given the books 760 pages there are many lessons can serve as a working example in the classroom They can also form the basis for homework assignments For example take the example on lists and implement the same idea using a database In this regard I have long felt that the Murach books are the ones Id use for teaching an introductory Java programming course However the books rarely reach beyond the introductory level nor claim to So advanced topics such as the complexities of concurrency are not explored This fifth edition adds coverage of Java 9 focusing mostly on the basics of modules and explaining the new requirements for how to compile and build programs A B java proposals of interest PROPOSED JDK ENHANCEMENT PROPOSAL Making Java Container Aware Theres no doubt that part of what makes microservices viable is the ability to deploy the services in a container that is in a stripped down virtualized environment such as Docker This JDK Enhancement Proposal JEP suggested by Bob Vandette of Oracles Embedded Java team seeks to define technology that makes Java inside a container container aware The principal problem it seeks to address is how Java can be made aware of container policies that might afect the Java runtime in particular being accurately informed of resource constraints Right now when the JVM starts up it obtains information about the CPU and the environment This information can be inaccurate if the physical configuration is set by command line switches for Docker containers The data the JVM collects can lead it to overestimate the memory available to it which leads to incorrect decisionmaking internally and ultimately to poor performance This proposal note that it has not yet reached the stage of a JEP suggests that a new API be developed that would capture the correct data for numerous configuration details of the container including memory limits and memory usage CPU counts sets and usage block I O details device I O read and write rates and host details such as shared memory size In whatever form it takes its clear that support for the use of Java in containers is likely to come to the language sooner rather than later When it does it will first appear in JEPs as proposed here and in Java Specification Requests JSRs