No.
C++ is a superset of C.
You can write C and jam it into a C++ program.
This happens often enough in C++ programs.
Java absolutely does count. The Sun JVM was written in C !!! So, yes, every java program is executing instructions generated by a C program.
A distinguishing characteristic of Jikes RVM is that it is
implemented in the Java™ programming language and is
self-hosted i.e., its Java code runs on itself without
requiring a second virtual machine. Most other virtual
machines for the Java platform are written in native code
(typically, C or C++). A Java implementation provides ease
of portability, and a seamless integration of virtual
machine and application resources such as objects, threads,
and operating-system interfaces.