Because iReport 5.1.0 requires Java 6 or 7 (both end-of-life), running it on a modern system with an unverified installer is extremely risky.
iReport Designer v5.1.0 Release Notes - Jaspersoft Community download jaspersoft ireport designer 5.1.0
Before you start coding reports, iReport needs to know which Java compiler to use. Because iReport 5
