IntelliJ IDEA
IntelliJ IDEA – the Leading Java and Kotlin IDE, by JetBrains
Features
Icons Preview in Gutter Bar
Maia supports preview of icons you are using in Java code directly from the editor. For each of the icon definitions (javax.swing.Icon), Maia tries to locate a file from which it is loaded and then shows a preview in the gutter bar. You can click it to open the image for editing, of course.