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Copying Generic Arrays in Java
2 months ago
- Copying generic arrays in Java is problematic due to type erasure, as generic array creation is not allowed directly.
- Using clone() on an existing array works to preserve order and create a new instance, but creating a new generic array via 'new T[]' is a compile-time error.
- Casting 'new Object[]' to a generic array type can lead to a ClassCastException at runtime with no traceback, pointing to the calling method instead of the faulty line.
- The Java compiler translates 'new T[]' into java.lang.reflect.Array.newInstance, which requires the actual class object; type parameters are erased and unavailable.
- A workaround is to obtain the class from an existing instance (e.g., via getClass()) or to return null if the array is empty, avoiding the need for reflection.
Intro to Python
2 months ago
- Python variables do not require explicit types, unlike Java where types must be declared (e.g., `i = 1` vs `int i = 1`).
- Python supports dynamic typing and duck-typing, allowing lists to hold mixed types (e.g., `l = [1, 1.2, 'hello, world']`), while Java requires generics or explicit typing.
- Python dictionaries can use non-integer keys (e.g., `{'Monday': 'MATH 374'}`), and indexing works similarly to lists.
- Python uses `**kwargs` to handle arbitrary keyword arguments in functions, whereas Java uses varargs with a functional interface like `IntConsumer`.
- Python's documentation uses triple-quoted strings with plain text, while Java's Javadoc uses `/** */` with HTML markup.
- Python's `print` function can be redefined to accept variable arguments using `*args`, similar to Java's varargs with `Object...`.
- Python supports lambda functions and higher-order functions (e.g., `call_with_one(lambda arg: print(arg))`) more syntactically flexibly than Java, which requires functional interfaces.
WASM on the JVM Ships Under the Bytecode Alliance
3 months ago
- Endive 1.0, the pure-Java WebAssembly runtime, has been officially released under the Bytecode Alliance.
- It replaces Chicory with minimal migration, offering the same API and codebase but under new governance.
- New features include full support for WasmGC, enabling integration with languages like Kotlin/Wasm and Dart, and tail call optimizations for improved performance.
- A new library, treesitter4j, compiles tree-sitter and its grammars to Wasm, providing a Java API for parsing various languages without JNI.
- Endive can host Wasm workloads, as demonstrated in a wasmCloud host and Eclipse Vert.x app, and has been stress-tested by running javac and Scala.js as Wasm.

Copying Generic Arrays in Java

Intro to Python

WASM on the JVM Ships Under the Bytecode Alliance