debug package doesn't add debug symbols to gdb

Hi,
I installed java jdk 11 with debug symbols:
openjdk-11-dbg/bionic-updates,bionic-security,now 10.0.2+13-1ubuntu0.18.04.4 amd64 [installed]
openjdk-11-jdk/bionic-updates,bionic-security,now 10.0.2+13-1ubuntu0.18.04.4 amd64 [installed,automatic]
openjdk-11-jdk-headless/bionic-updates,bionic-security,now 10.0.2+13-1ubuntu0.18.04.4 amd64 [installed,automatic]

However, when I try to debug java application with gdb, I don't see method definition and variables names.
But I can add breakpoints to the native methods. For example, I can't add break and stop at Java_java_io_FileOutputStream_writeBytes, but don't see sources of this method.

(gdb) break Java_java_io_FileOutputStream_writeBytes
Breakpoint 1 at 0x7fddab8ab6f0
(gdb) list Java_java_io_FileOutputStream_writeBytes
(gdb)