public void aMethod (MultipleObjects object){

object.commonMethod();
// Do some stuff here
}

interface MyInterface {

    void commonMethod();

}

class MyClass implements MyInterface {

    // implement `commonMethod()`

}

public void aMethod(MyInterface object) {
    ...
    object.commonMethod();
    ...
}

public void aMethod(SomeInterface obj) {
    obj.commonMethod();
    // ...
}

public interface SomeInterface {
    public void commonMethod();
}

interface CommonMethodHaver {
     void commonMethod();
}

class Class1 implements CommonMethodHaver {
     yadda yadda yadda;
     void commonMethod() {
         do class1-specific stuff here;
     }
}

...
public void aMethod(CommonMethodHaver cmh) {
    cmh.commonMethod();
    // Do some stuff here
}

public void aMethod(Object... object) {
if(object==null)
{
    //whatever you want to do if no parameters are entered.
    return;
}
for (Object o : object) {
    if (o == null) {
    continue; //what to do if null entered
    }
    if (o instanceof Integer) {
    //whatever you want to do if it is an Integer
    }
    else if(o instanceof Double)
    {
    //whatever you want to do if it is a Double
    }
    else if(o instanceof Character)
    {
    //whatever you want to do if it is a Character
    }
    //and so on
 }
}