Category Archives: Java/Java EE

gradle in eclipse – egradle vs buildship

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TLDR: use BuildShip rather than EGradle.

While everyone on our team uses command line git (rather than egit), most actual coding in Java happens within Eclipse. We ran Ant in Eclipse for deploying robot code and Ant at the command line for other things. I’m not sure if we will use Eclipse to run Gradle, but writing up for the team just in case!

For more on what the Gradle files mean see the main Gradle SmartDashboard post

EGradle

The first thing I did was try out the EGradle plugin. It worked, but wasn’t as smooth as BuildShip. (See below for using BuildShip).

Install EGradle

  1. Help
  2. Eclipse Marketplace
  3. EGradle
  4. Accept license and install
  5. Restart Eclipse

Modify the project you cloned from github

  1. Clone SmartDashboard if you haven’t already
  2. Edit the build.gradle file to add the eclipse profile.  You just have to add the one line and save the file: 
    project(':fakeRobot') {
  apply plugin: 'java'
  apply plugin: 'application'
  apply plugin: 'eclipse'

Import the project you cloned from github

  1. File
  2. Import
  3. EGradle > Import gradle root project with all subprojects
  4. Set Gradle root project to the repository you cloned from github

Build

  1. Right click the build.gradle file
  2. Run as > EGradle

EGradle limitations

  1. You had to edit the build.gradle for Eclipse to recognize it.
  2. EGradle doesn’t provide a way to see the build directory so you have to go to the file system. (and yes I tried changing the filters; it just didn’t work)

Trying that again with BuildShip

BuildShip is the official Eclipse.org plugin for Gradle. Wish I knew that before I started!

Install BuildShip

  1. Help
  2. Eclipse Marketplace
  3. BuildShip Gradle Integration
  4. Accept license and install
  5. Restart Eclipse

Import the project you cloned from github

  1. File
  2. Import
  3. Gradle >Existing Gradle project
  4. Set project root directory to the repository you cloned from github (Note that you don’t need to edit the build.gradle file like you had to with EGradle). It also uses the proper project name.

Build

There are multiple ways to do this. I’m showing just one way that maximizes understanding of what is going on.

  1. The Gradle Tasks view is open automatically for this project. (If not, click the project)
  2. Click SmartDashboard to expand
  3. Click build to expand
  4. Right click build (with a green icon to the left) and choose “Run Gradle Tasks”
  5. This automatically opens the Gradle Executions view which shows you what Gradle did in a nice tree. You can click on the Console view to see the actual command line output.
  6. Configure the filters so you can see the Gradle build folder
  7.  F5 to refresh – now you see the build folder.

 

The 8 Nights of Java – Night 8

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It’s been a fun 8 Nights of Java, but alas, tonight is the final post. Java 8 added one of the most radical, most drastic changes to date, even bigger than Java 5 or Java 7: lambdas and streams! The writers of Java updated nearly every Java API to include lambda expression and stream-based methods. More than the API changes, though, they present a new paradigm for thinking about programming. The closest thing to a lambda expression prior to Java 8 was an anonymous inner class, and it a lot of ways they are similar, but the syntax and usability of lambda expressions is unmatched.

We hope everyone had a wonderful holiday season and we hope that you have a Happy New Year! Don’t forget, we have a brand new OCA/OCP 8 book coming out in March 2017. Order yours now on Amazon.com!

Jump to: [Night 1 | Night 2 | Night 3 | Night 4 | Night 5 | Night 6 | Night 7 | Night 8]

Java 8 Notable Features

Oracle released Java 8 on March 18, 2014. If you’ve read the previous nights in this series, you might be wondering what the codename of Java 8 was. Oracle decided not to use one. Luckily, our friends at the Javaranch had some ideas. We like “Cuddles” ourselves.

Key new functionality included:

  • Functional interfaces
  • Lambda expressions
  • Streams
  • New date/time library
  • Project Nashorn

From Jeanne:

Streams and lambdas are one of my favorite additions to the language of all time. They make it easy to write expressive code. I haven’t needed the benefits of multi-core parallelization much yet, but it is nice to know it is there. Even without that, I find my stream based code to be shorter and easy to write/read. It took me a little while to get fluent but I went through that with Groovy before Java so I was ready when it came to Java. I was the first person on my team to write a Java 8 program for work. I commented almost every line so it could be used as a teaching example. That was fun!

The date/time library is also cool. I like that it is expressive and has so much more functionality than the Calendar API. Third time for a date API really was the charm. I just wish they retrofitted it to work directly with more libraries like JDBC. Then there’s Nashorn. A JavaScript console was a good idea, but I don’t think this one is it.

From Scott:

Two things I love about lambda expressions and streams in Java 8. First, they found a way to build functional programming into Java, by using functional interfaces. While the signature for some of the built-in functional interfaces can be… hard to read… using or creating lambda expressions rarely requires understanding the signature. That’s what is so cool about what they did. They added this conversion of lambda expressions to functional interfaces to anonymous inner classes, but from a developers perspective, all we have to know how to do is write a simple one-line lambda expression! Very cool they way they added this on without breaking the language.

The second thing I love is they included parallel streams in the very first version! It’s so awesome to be able to have built-in easy support for concurrency without having to create/manage/shutdown an executor service. One feature request for Java 9? I *really* would prefer a way to set the number of threads in a parallel stream, such as stream.parallel(10) for 10 threads. Currently, it’s controlled by the JVM based on the number of threads on the computer and unable to be changed by a developer. Here’s hoping they add it to a future version of Java!

There’s still so much more to love about Java 8! As I was saying on Night 7, Java 7 improved the Concurrency API while introducing NIO.2, but both became even more powerful in Java 8. Creating Runnable and Callable instances using anonymous inner classes was already common prior to Java 8, but it was at times verbose. You had to create a class definition, override a method, set up a generic return type for Callable, etc. While not difficult to do, it did take up multiple lines of bloated code, copied over and over again for each task. Lambda expressions fit perfectly in the Concurrency API, better than any other API (with the possible exception of Collections), in that it allowed developers to submit tasks to a thread executor in a single, simple line of code using a lambda expression. In other words, they made Concurrency, one of the arguably most difficult spaces for developers to work in, much easier to understand and implement.

The 8 Nights of Java – Night 7

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Our 8 Nights of Java series is nearly at an end! Tonight we look at Java 7, the first version of Java released entirely by Oracle. Java 7 included many goodies for developers, in the form of Project Coin. In a lot of ways, Project Coin was straight off of most developers Top 10 Wish List. Like Java 5, many of the futures were compile-time enhancements and helped to simplify numerous lines of code down to just one, allowing developers to focus on the important logic in their classes rather than syntax.

Jump to: [Night 1 | Night 2 | Night 3 | Night 4 | Night 5 | Night 6 | Night 7 | Night 8]

Java 7 Notable Features
Oracle released Java 7 (codename Dolphin) on July 7, 2011. After 5 years of Java 6 (including 131 updates) and the acquisition of Sun by Oracle, it was finally time to add some new features to Java. Key new functionality included:

  • Project Coin:
    • Strings in switch statements
    • Underscores (_) in numbers
    • Diamond (<>) operator
    • try-with-resources statement
    • Multi-catch blocks
    • Binary literals
  • NIO.2
  • Expanded Concurrency API

From Scott:

I love Java 7. While Java 5 “fixed” Collections by adding generics/autoboxing/foreach loops, Java 7 greatly improved the language by adding things that I didn’t even realize I was missing. The greatest of those (for a database-driven developer such as myself) was the try-with-resources statement. We’ve spoken in the past about finally closing JDBC resources, and to be honest, even we forget to do them sometimes. Could you blame us? The syntax was horrible. Especially because close() throws a checked exception which often must be caught inside another catch block! The try-with-resources statement fixed this not only by designing a syntax that was simple and easy to use, but finally providing a “standard” for all developers to work off of. After Java 7 was released, if I came across another developer opening/closing a connection without a try-with-resources statement, I could instruct them to replace it with one that does, thereby ensuring any possible resource leak is closed.

Project Coin had many other, very useful features. Strings in switch statements had been requested by numerous developers, especially beginners learning Java, for the better part of a decade. The diamond operator, while seemingly simply, greatly reduces assignments involving embedded Collections… such as “new HashMap<String,List<Integer>>” to just “new HashMap<>”. It was a pain to write out the full generic expression on both sides of an assignment! I don’t tend to use binary literatals or underscores in numbers, but I’m thrilled they were added to Java 7 since it makes reading other developers code a lot easier.

So many awesome features for developers in Java, I haven’t even gotten to the improved Concurrency API and new NIO.2. Both are extremely powerful, fully developed libraries that you can use to developer complex applications in minutes. And both got even better in Java 8 with the inclusion of… oops! Guess we’ll have to wait till tomorrow night to finish that sentence!

From Jeanne:

When I was young, the local college built a science building and named it the “New Science Building.” It’s still called that.The problem is what you call the one after that. NIO.2 had the same problem. “New I/O” didn’t take so well and now the name is taken. Luckily NIO.2 is nice! I use it a lot in my coding because I do a lot of file system work. I find myself using Apache Commons for I/O operations very rarely now.

Then there is Project Coin. While some is just semantic sugar like the diamond operator, it still makes the code cleaner and less redundant. The try with resources is great for not having to deal with boilerplate code! I also appreciate multi-catch. Before it existed, I’d often revert to “throws Exception” rather than independently catch two or three exceptions and handle them the same way. This happened a lot with a framework we used that declared two checked exceptions. It also happened a lot with XML parsing and reflection. With multi-catch, I’m more inclined to do the right thing and handle them all in one line.