Start coding Java8(early access) simple 3 step.

Impressed JavaOne2013

1.download & install Java8(early access)

You can download Java8 early access version from here.
https://jdk8.java.net/download.html

2.choose IDE

You can use NetBeans or IntelliJ for coding by Java8.
Now, Eclipse doesn't support Java8 yet.

NetBeans
http://bits.netbeans.org/dev/nightly/latest/

IntelliJ(Community version is free)
http://www.jetbrains.com/idea/download/

3.(IntteliJ)Using java8 in IDE

Create new project

Add jdk8(Project SDK) you installed.

Here is the default java path(mac).

ls -ltr /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/bin/java
-rwxrwxr-x  1 root  wheel  99296  6 14 06:57 /Library/Java/JavaVirtualMachines/jdk1.8.0.jdk/Contents/Home/bin/java

Create Java class.

Let's Cording.