[jan@jan src]$ javac test.java 
test.java:3: cannot find symbol
symbol  : variable UIManager
location: class test
	System.out.println(UIManager.getSystemLookAndFeelClassName());
	                   ^
1 error

[jan@jan src]$ cat test.java 
class test {
public static void main(String[] args){
	System.out.println(UIManager.getSystemLookAndFeelClassName());
	}
}