Another example using the pi4j library, this time displaying various clock speeds on your system
import com.pi4j.system.NetworkInfo;
import com.pi4j.system.SystemInfo;
import java.io.IOException;
import java.text.ParseException;
public class clockinfo
{
public static void main(String[] args) throws InterruptedException, IOException, ParseException
{
System.out.println("----------------------------------------------------");
System.out.println("CLOCK INFO");
System.out.println("----------------------------------------------------");
System.out.println("ARM Frequency : " + SystemInfo.getClockFrequencyArm());
System.out.println("CORE Frequency : " + SystemInfo.getClockFrequencyCore());
System.out.println("H264 Frequency : " + SystemInfo.getClockFrequencyH264());
System.out.println("ISP Frequency : " + SystemInfo.getClockFrequencyISP());
System.out.println("V3D Frequency : " + SystemInfo.getClockFrequencyV3D());
System.out.println("UART Frequency : " + SystemInfo.getClockFrequencyUART());
System.out.println("PWM Frequency : " + SystemInfo.getClockFrequencyPWM());
System.out.println("EMMC Frequency : " + SystemInfo.getClockFrequencyEMMC());
System.out.println("Pixel Frequency : " + SystemInfo.getClockFrequencyPixel());
System.out.println("VEC Frequency : " + SystemInfo.getClockFrequencyVEC());
System.out.println("HDMI Frequency : " + SystemInfo.getClockFrequencyHDMI());
System.out.println("DPI Frequency : " + SystemInfo.getClockFrequencyDPI());
System.out.println();
System.out.println();
}
}