how to make a jigsaw puzzle in powerpoint

I wanted to have an image of Duke (the Java mascot) as a jigsaw puzzle image for a presentation. First I googled and couldn’t find an existing one.  I found one on a blog, but it doesn’t look good from the distance. Also, it isn’t labeled for reuse.

So rather than work on content for my presentation, I decided to learn how to make a jigsaw puzzle image. It wasn’t hard.

Step 1 – get an image

I decided to use this image of Duke as a stuffed animal that I found online. I was thinking about using a picture of me and Duke but the lighting was too dark to come out well on a slide.

Step 2 – get a jigsaw puzzle template

I found this template online.

Step 3 – combine

  1. Open the template in PowerPoint.
  2. Import/paste the image on the slide you want to use. for me, this was slide 5 – the blank template for a photo.
  3. Resize the photo/image to be the same size as the puzzle and overlay it.
  4. Right click your photo/image and choose “Arrange -> Send to Back”
  5. Select all 12 puzzle pieces (I had to do this manually rather than with command A)
  6. Right click -> format object
  7. Choose fill and select 100% for the transparency
  8. Choose line and select black
  9. Select all and choose arrange > group

Now you have a single image that you can use in your own deck.

The result

duke jigsaw

DevNexus 2018 – Modules in Action

Title: Modules in Action
Speakers: Mark Reinhold

For more blog posts, see the DevNexus 2018 live blogging table of contents

Demo used Java 10 RC.

Using JShell to look at modules

  • “foo”.getClass().getModule() – module java.base
  • “foo”.getClass().getModule().getClass() – class java.lang.Module
  • new java.sql.Timestamp(0).getModule() – module java.sql


  • java –list-modules – ex: java.sql@10
  • There are 75 modules in Open JDK 10


  • The Java 9 JavaDoc shows modules on the home page instead of all the packages.
  • Clicking a module shows you the packages in the module.
  • Java 9 JavaDoc has search box

Random facts

  • tree – unix commands that list what is in directory and children (not installed by default)
  • Showed that can use * in classpath to get all files in lib directory. (since Java 6)

Creating a bare bones module

  • Create file in root of src folder
  • Simplest module file is one line: module moduleName { }
  • If run javap against the class file, you can see “requires java.base;” was added. This is like a constructor calling super(). It is mandatory so you don’t need to type it.
  • jar –file x.jar –describe-module – shows name of file, requires and the package contained
  • java –module-path lib -m moduleName/className – run the program
  • java -classpath jar className – can still run a modular jar on the classpath
  • jar –create –file x.jar –main-class class -C classes – create a jar that can run without specifying the class to run
  • java –modulepath lib -m moduleName – run the program without specifying it by name

Refactoring the module to split into two

  • module module1 { requires packageName; }
  • module module2 { exports packageName; }


  • If remove module2 and try to run, get java.lang.module.FindException on startup since can’t find module. Error inlcudes “Error occurred during initialization of boot layer”
  • If forgot to type “requires”, and compile get “package x is not visible”
  • If two modules require each other and compile, get “cyclic dependence involving package x”
  • If forget to type “exports” and compile, get “IllegalAccessError exception” along with long message about exporting


  • Optional Java linker
  • New directory jmods in JAVA_HOME.
  • Each module in the JDK has a file in jmods
  • JDK got a lot bigger with Java 9 because shipping two copies of each module – the main one and the jmods directory
  • jlink –module-path $JAVA_HOME.jmods –output jre –add-modules java.base – creates a JRE that is an order of magnitude smaller than the full one (44M vs 329B)
  • Can include your custom app into the image in addition to JDK
  • jlink –module-path $JAVA_HOME.jmods:lib –output jrePlusApp –add-modules java.base myCustomModule
  • jlink has a –compress flag to make file smaller
  • Not platform independent. Can cross link to create file for other operating system


  • Want to make it so private really means private and final really means final. Vs reflection today.
  • Illegal reflective access – first time, get warning. The warning tells you how to enable more warnings. There probably are, but don’t want to blast you with them. Eventually, warning will turn into a hard error.
  • Not planning to disallow illegal reflective access until after Java 11.
  • Supplementing “exports”, is “open. It allows extra reflection

Inside a jmod

  • jmods are like a zip file with extra structure.
  • classes directory with all of the classes
  • conf directory for files in runtime image
  • include directory for jni header files
  • legal directory with licenses if any
  • bin directory for launchers
  • lib directory for native code

My take

I like the live demo approach along with the emphasis on both concepts and common problems. I also like that Mark left a lot of time for Q&A.


JavaOne – Project Jigsaw – Integration with Tools

“Project Jigsaw – Integration with Tools”

Speaker: Alexandru Jecan (author of Java 9 Modularity Revealed)

For more blog posts from JavaOne, see the table of contents

What expect build tools and IDEs to do

  • Code completion (IDEs only)
  • Make things easier
  • Work with class path and module path


  • Only Maven 3+ supports Java 9.
  • No changes to Maven core to run on Java 9
  • presence of decides if Maven uses module path
  • Need Maven compiler plugin 3.6.1 to compile Java 9 code
  • Discourages using automatic module name
  • GAV not related to module name. Continue to use GAV.
  • Use module name in – double work
  • Maven does not generate “requires” clauses for
  • Can add <compilerArgs> options for -add-modules or -add-exports
  • New tag <release> which takes precedence over source/target tags. Recomended compiling twice or backward compatbility. once for java 9 modules and once for java 8. [why? isn’t that what multi release ars are for?]
  • maven-exec-plugin – can configure module path
  • taked abut updating maven toolchain file [not clear how this differs than prior versions of java]
  • maven-jdeps-plugin – can automatically generate module descriptor [but said earlier couldn’t]
  • maven-jmod-plugin – new plugin; not yet released. Creates and lists content of jmod files. Merge native code into jar
  • maven-jlink-plugin – new plugin; not yet released. Creates runtime images
  • maven-depdendency-plugin – said lists GAV [not clear how changed

No first class support for Java 9 yet. Coming soon. [but said using; puzled?]

Ant 1.9.8+ support JDK 9 modules for java/javac/junit. [yet Ant doesn’t support JUnit 5]


  • New build tool for Java 9
  • Uses YAML config. Uses Maaven repo.
  • Supports JUnit 5,

Maven plugin that generates based on dependencies. Says helps a little but doesn’t do all the work. [how?]

SonarJava 4.11+ recognizes module keywords

Open source visualization software
Reads jdeps input to generate graphical representation of Jigsaw. As can IDES


  • NetBeans, Eclipse and IntelliJ all understand modules clauses [if you count pre-release versions]
  • Also offer autocompletion, syntax higlighting, etc
  • NetBeans 9 – not yet released; must build yourself. Showed editing module path, visual of module dependencies, jshell, jlink
  • Eclipse Oxygen with Java 9 support – came out 9/27/17. Ten second demo
  • IntelliJ 2017.1+ – Mark directory as source root so directory name matches module name. Errors on common module errors, Showed module editing, module dependencies and other features

Open source readiness

How to modularize your app

  • Introduce by creating manually or running jdeps to generate
  • Problems: using JDK internal APIs (ignore warning or fix), using odule not availalbe such as xml bindings (add-modules at compile and runtime), cyclic dependencies (can have at runtime but not compile time), split packages (Oracle plans to make change in later version of Java to deal with this)
  • [Note: He recommended renaming packags as a solution to spit packages. That sounds like a horrible idea unless you can guarantee only you call that code]

    My take before session: You know how they say that first impressions matter? The speaker is wearing a suit. 90% of the people in the room are wearing jeans. Two people in the room are wearing a suit The speaker and someone he knows. Then he showed the table of contents. There are 29 points in 45 minutes in the outline. Preparing to have my head spin!

    My take after session: He is in fact technical. The suit was misleading! The pace was way too fast though; drinking from a fire hose. Not enough time to understand/process many of the points. He talks fast (as do I), but key is to *pause* if you talk fast so people can catch up. Also the side transitions were distracting. A cube transition is cute. But if you are reading when it moves, it is disorienting. And due to the speed, there was a good chance of being reading when transitions started. This was good information, but should have been two sessions so split up and a decent pace. And omiting how to migrate your libraries; that’s a talk on its own There is a Maven BOF tonight; maybe folks can discuss more then!

    One minute after the official end time, he asked if there were questions. My head was spinning with questions. [I didn’t even have time to process which was most important]. Another attendee asked if having JUnit tests in a parallel directory with the same package name is a split package. The speaker said yes and went on to say to wait for Java 10 or rename. I interjected at that point. Unless you are distributing a test jar, I don’t think this is a problem. In fact, most IDEs compile both the /src/main/java and /test/main/java directories to the same folder. I stated this and asked the speaker if he agreed. He said yes.