If Java had been able to provide it historically, "cross-platform sandboxed acceptable-to-high-performance execution of untrusted code" effectively describes WA

If Java had been able to provide it historically, "cross-platform sandboxed acceptable-to-high-performance execution of untrusted code" effectively describes WASM, which seems to be a fairly major emerging technology these days. Perhaps JVM bytecode is arguably just too complex for safe verification... (although JavaCard interpreters manage to do it for a restricted subset (with similar restrictions to WASM!) without too many problems)