[ptx]

Sure, an AOT compiler for Java would solve some of these issues, at the cost of larger binaries and loss of the dynamic runtime optimizations that make Java fast for long-running programs (which is why Android uses a combination of AOT and JIT). Some people on this site often point out that expensive commercial AOT Java compilers have been around for a long time. JetBrains even used to provide an AOT-compiled binary of the Kotlin compiler for a while.

However, you were asking why people consider Java to be heavy. When people normally use or talk about Java, Java means a JRE derived from Sun's Java implementation. If you download Java to run the Kotlin compiler or IntelliJ, you're not downloading the Android runtime or some hypothetical AOT compiler - you're using something based on OpenJDK, which suffers from the heaviness I described.