Obtain timestamp string in Java.

In Java, you can use the System.currentTimeMillis() method to get the current time timestamp, which returns a long type value. If you need to convert the timestamp to a string, you can use the String.valueOf() method to convert the long type to a string type.

Here is an example:

long timestamp = System.currentTimeMillis();
String timestampString = String.valueOf(timestamp);
System.out.println(timestampString);

The output will be similar to: 1578467512345