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
Because this version is no longer actively supported, you must use archival sources for the download:
The primary source for the installer is the iReport Project on SourceForge, which includes the Windows installer ( .exe ), Mac DMGs, and Linux binaries ( .tar.gz ). jaspersoft ireport designer 4.0.1 download
iReport Designer v4.0.1 Release Notes - Jaspersoft Community
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. Jaspersoft iReport Designer 4
iReport 4.0.1 requires JDK 1.5 or 1.6 . It is notoriously incompatible with Java 8 or higher.
Improved CSV datasource support and new namespace-aware query executors. iReport Designer v4
Are you planning to to a newer version, or do you need to fix a specific error in an old 4.0.1 environment?