Worked on the apache/groovy repository to enhance UI framework stability and customization within Java Swing applications. Addressed compatibility issues by removing deprecated JApplet checks in SwingBuilder, ensuring smooth operation on Java 26 and newer, which reduces runtime exceptions and future-proofs the codebase. Introduced Nimbus Look and Feel support, expanding available UI theming options and improving consistency for end users. Leveraged Groovy and Java to implement these changes, focusing on robust UI development practices. The work delivered both a feature and a bug fix, demonstrating attention to evolving platform requirements and a commitment to maintaining reliable, customizable user interfaces.