java.lang.IllegalArgumentException: Negative length on strings concatenation

Please excuse for messy generated test (attached).

The issue happens during concatenation of relatively large strings (about a 1MB size). I would expect any other error, like OutOfMemoryError, but not a 'Negative length' given that the expression being evaluated only contains strings and '+' operators.

The exception:
java.lang.IllegalArgumentException: Negative length
        at java.base/jdk.internal.misc.Unsafe.allocateUninitializedArray(Unsafe.java:1378)
        at java.base/java.lang.StringConcatHelper.newArray(StringConcatHelper.java:438)
        at Test_38.method_int_int_287(Test_38.java:2215)
        at Test_38.method_float_float_435(Test_38.java:2312)
        at Test_38.mainTest(Test_38.java:2449)
        at Test_38.main(Test_38.java:2464)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
        at java.base/java.lang.reflect.Method.invoke(Method.java:578)
        at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:125)
        at java.base/java.lang.Thread.run(Thread.java:1591)