B4J Version: 10.20
Parsing code. (0.03s)
Java Version: 8
Building folders structure. (0.14s)
Compiling code. (0.60s)
Compiling layouts code. (0.01s)
Organizing libraries. (0.00s)
Compiling generated Java code. Error
javac 1.8.0_321
src\b4j\example\pyutils.java:1286: error: cannot find symbol
public static void registerMultipleKeys(java.util.List<Object> objects, java.util.List<Integer> keys, java.lang.ref.Cleaner cleaner) {
^
symbol: class Cleaner
location: package java.lang.ref
1 error