Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
Eclipse - Eclipse is an open source community, whose projects are focused on building an open development platform comprised of extensible frameworks, tools and runtimes for building, deploying and managing software across the lifecycle.
BuildFire - BuildFire is the easiest way for small businesses to build a mobile app in a matter of minutes for iOS and Android.
IntelliJ IDEA - Capable and Ergonomic IDE for JVM
MIT App Inventor - App Inventor is a cloud-based tool, which means you can create apps for phones or tablets right in your web browser.
BlueJ - BlueJ is an Integrated Development Environment for Java, developed mainly for educational purposes...