iReport 4.0.1 requires JDK 1.5 or 1.6 . It is notoriously incompatible with Java 8 or higher.
Resolved common copy-paste issues for variables and fixed the "Bring to Front/Send to Back" UI commands. jaspersoft ireport designer 4.0.1 download
If you use the NetBeans IDE, you can find the plugin version (NBM files) on the Jaspersoft Community Knowledge Base . iReport 4
Since the "end of life" announcement in 2015, users are strongly encouraged to migrate to Jaspersoft Studio . This Eclipse-based tool can import existing .jrxml files and offers better compatibility with modern operating systems and Java versions. If you use the NetBeans IDE, you can
Includes a fully dockable interface, report inspector, and built-in expression editor. Installation & Compatibility
Jaspersoft iReport Designer 4.0.1 is a legacy visual report design tool used to create templates for the JasperReports Library. While it was officially replaced by Jaspersoft Studio in 2015, many developers still require version 4.0.1 to maintain older "pixel-perfect" reports. Download Options for iReport Designer 4.0.1