メソッド参照できる・できない

MethodReferenceExample.java

package example;

// https://ideone.com/cx8hsF
public class MethodReferenceExample {
	public static void main(String[] args) throws java.lang.Exception {
		// your code goes here
		Test test11 = String::trim;
		// Test test12 = Hogehoge::trim; // NG

		Hogehoge h = new Hogehoge();
		Test test13 = h::trim;

		Test test14 = Hogehoge::staticTrim;

		// Test2 test21 = String::trim; // NG
		Test2 test22 = Hogehoge::trim;
	}
}

class Hogehoge {
	String trim(String v) {
		return v.trim();
	}

	static String staticTrim(String v) {
		return v.trim();
	}
}

interface Test {
	String doSomething(String v);
}

interface Test2 {
	String doSomething(Hogehoge hh, String v);
}