compilation - Execution Java -cp -

i have doubt -cp , when should use it. scenario: have 2 .java, first one:

package autos.tests.paquete;

public class mainautos {

public static void main(string args[]) {  int x = integer.parseint(args[0]);  respotar objeto1 = new respotar (x);   int mostrar = objeto1.repostar();   system.out.println(mostrar); 

} }

and second one:

package autos.tests.paquete;

public class respotar {

int gasolina;  public respotar (int gasolina) {      this.gasolina=gasolina;  }   public int repostar (){      int gasolina = this.gasolina +20;        return  gasolina; } 

}

well, @ root directory, , there, have directory: autos/tests/paquete both .java.

so compile: javac autos/tests/paquete/*.java

and execute root directory: java autos.tests.paquete.mainautos 10 , works, here go doubts:

1) execute java -cp . autos.tests.paquete.main autos 10 , behaviour same.

2) move respotar.class auto/tests/paquete directory, compile java autos.tests.paquete.mainautos 10 , works.

3) move mainautos.class auto/tests/paquete directory, compile java autos.tests.paquete.mainautos 10 , says: error: not find or load main class autos.tests.paquete.mainautos

4) compile java -cp . autos.tests.paquete.mainautos (i have .class on current directory compiling, think have use -cp .) , says same: error: not find or load main class autos.tests.paquete.mainautos

thank in advance, hope can enlighten me, regards

java -cp used set libraries such jar file current classpath.

for examples have shown, can in below simple way

from root directory compile java files using below command

javac -d . *.java 

this created appropriate packages , place class files under them

then run code using command same root location

java autos.tests.paquete.mainautos