{"id":1940,"date":"2018-06-13T02:39:35","date_gmt":"2018-06-13T02:39:35","guid":{"rendered":"http:\/\/www.talkcrypto.org\/blog\/?p=1940"},"modified":"2018-07-06T21:42:41","modified_gmt":"2018-07-06T21:42:41","slug":"hashgraph-hello-world","status":"publish","type":"post","link":"https:\/\/www.talkcrypto.org\/blog\/2018\/06\/13\/hashgraph-hello-world\/","title":{"rendered":"Hashgraph Hello World"},"content":{"rendered":"

If you’ve heard about Hashgraph and wondering how to get started, here is a little guide based off the docs provided in the SDK. Running the demo is easy but preparing your system can take a little bit of time. (Just like cooking!)<\/p>\n

A good place to start is\u00a0https:\/\/www.hederahashgraph.com\/<\/a>\u00a0where you can read a bit about it but there is a section for developers which points you to\u00a0https:\/\/dev.hashgraph.com\/<\/a>\u00a0which is where the good stuff is.<\/p>\n

There is a “How do I get started?” section which is where you … start. The instructions are at:\u00a0https:\/\/dev.hashgraph.com\/docs\/installation\/<\/a><\/p>\n

Pre flight check list<\/h2>\n

Step 1: JDK 8<\/h3>\n

You need at least JDK 8 otherwise you’ll get an error like this:<\/p>\n

> cloudnthings$ java -jar swirlds.jar <\/span>\r\n> Exception in thread \"main\" java.lang.UnsupportedClassVersionError: com\/swirlds\/platform\/Browser :\r\n Unsupported major.minor version 52.0<\/span><\/pre>\n
If you are on a Mac, you want to run:<\/p>\n
> java -version\r\njava version \"1.8.0_171\"<\/span>\r\nJava(TM) SE Runtime Environment (build 1.8.0_171-b11)<\/span>\r\nJava HotSpot(TM) 64-Bit Server VM (build 25.171-b11, mixed mode)<\/span><\/pre>\n
and make sure you get a response like above. Otherwise go to Oracle<\/a>\u00a0and download the Java SE Development Kit.<\/p>\n
\"\"<\/p>\n
Go through the installation process and you should see a folder called\u00a0jdk1.8.0_171.jdk at \/Library\/Java\/JavaVirtualMachines\/<\/p>\n
Run the java -version command again to verify.<\/p>\n
Step 2: JCE Unlimited Policy for Java 8<\/h3>\n
Next download\u00a0Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files 8 from here<\/a>\u00a0and paste it to\u00a0\/Library\/Java\/JavaVirtualMachines\/jdk1.8.0_161.jdk\/Contents\/Home\/jre\/lib\/security\/policy\/unlimited. Otherwise you’ll get this error.<\/p>\n
\"\"<\/p>\n
Note: When I tried to do a clean install of Java and repeat the process from scratch I found that I didn’t get this error which is a little strange.\u00a0I found the 2 files were already at: \/Library\/Java\/JavaVirtualMachines\/jdk1.8.0_161.jdk\/Contents\/Home\/jre\/lib\/security\/policy\/unlimited<\/p>\n
Step 3: Download the SDK<\/h3>\n
Go to\u00a0https:\/\/www.swirlds.com\/download\/<\/a>\u00a0and download the SDK, extract it and then navigate to the sdk folder and run the following command in step 4 in a terminal.<\/p>\n
Step 4: Run this command<\/h3>\n
> java -jar swirlds.jar<\/pre>\n
This is what you should see:<\/p>\n
\"\"<\/p>\n
Congrats! You have your first Hashgraph application up and running. This is called the “Stats Demo” and is the default demo that runs when the\u00a0\u00a0> java -jar swirlds.jar command is run or if the swirlds.jar file is double clicked.<\/p>\n
It displays basic statistics such as:<\/p>\n