Jenkins transfer variable to other job

Goto JOB_1 and add a Post-Build action (Trigger parameterized build on other projects)
Type the project to build JOB_2
Add Parameters (Predefined Parameters)
Type the following in the Parameters box: test1=${test1}
Apply and Save
MOST IMPORTANT: YOU MUST ADD THIS PARAMETER (test1) to JOB_2
Goto and check "This build is parameterized" and add a "String Parameter"
Type "test1" (Must be same name) and put in a default value 

It's now an environment variable, to access it, all you need is $test1
In your build step,

ie echo $test1  and it will display