swig and java. How to make a simple example work?

Question

Java

Initial data:
example.h:

#ifndef _BRIDJ_EXAMPLE_H
#define _BRIDJ_EXAMPLE_H
namespace nl4j {
  class SomeClass {
    int m_value;
  public:
    SomeClass(int value);
    int someMethod(const char* message);
  void someCppFunction(const char* message);        
        };
}
#endif // _BRIDJ_EXAMPLE_H

example.i

%module example 
%{
#include "example.h"
%}
%include "example.h"

We collect our cpp and generated by swig in so, when trying to create an object from java: Error:
SomeClass cl = new SomeClass(6);

Exception in thread "main" java.lang.UnsatisfiedLinkError: com.mycompany.testswig.exampleJNI.new_SomeClass(I)J
  at com.mycompany.testswig.exampleJNI.new_SomeClass(Native Method)
  at com.mycompany.testswig.SomeClass.<init>(SomeClass.java:38)
  at com.mycompany.testswig.runme.main(runme.java:18)

Trying another option:
example.i

%module example 
%{
#include "example.h"
%}
int someMethod(const char* message);
void someCppFunction(const char* message); 
%include "example.h"

team:

gcc -fPIC -o libexample.so example.cpp example_wrap.cxx -I /usr/lib/jvm/java-8-openjdk-amd64/include/ -I /usr/lib/jvm/java-8-openjdk-amd64/include/linux/ -shared

Generated cxx does not compile:

example_wrap.cxx: In function ‘jint Java_exampleJNI_someMethod(JNIEnv*, jclass, jstring)’:
example_wrap.cxx:252:46: error: ‘someMethod’ was not declared in this scope
   result = (int)someMethod((char const *)arg1);