In JDK-8223657 one of the calls to intern strings was updated incorrectly:

--- a/src/hotspot/share/jvmci/compilerRuntime.cpp Tue May 14 11:28:44 2019 -0400
+++ b/src/hotspot/share/jvmci/compilerRuntime.cpp Tue May 14 11:29:18 2019 -0400
@@ -45,8 +45,7 @@
       // First 2 bytes of name contains length (number of bytes).
       int len = Bytes::get_Java_u2((address)name);
       name += 2;
- TempNewSymbol sym = SymbolTable::new_symbol(name, len, CHECK);
- str = StringTable::intern(sym, CHECK);
+ str = StringTable::intern(name, CHECK);
       assert(java_lang_String::is_instance(str), "must be string");
       *(oop*)string_result = str; // Store result
     }
@@ -78,7 +77,7 @@
     name++;
     len -= 2;
   }

The old code uses the u2 constant to specify the length of the name. The new code will use UTF8::unicode_length(utf8_string); (in StringTable::intern) to calculate the length. However, the string is not NUL terminated.