get current date and time in groovy?

Date has the time part, so we only need to extract it from Date

I personally prefer the default format parameter of the Date when date and time needs to be separated instead of using the extra SimpleDateFormat

Date date = new Date()
String datePart = date.format("dd/MM/yyyy")
String timePart = date.format("HH:mm:ss")

println "datePart : " + datePart + "\ttimePart : " + timePart

A oneliner to print timestamp of your local timezone:

String.format('%tF %<tH:%<tM', java.time.LocalDateTime.now())

Output for example: 2021-12-05 13:20

#!groovy
import java.text.SimpleDateFormat
pipeline {
    agent any
    stages {
        stage('Hello') {
            steps {
                script{
                def date = new Date()
                sdf = new SimpleDateFormat("MM/dd/yyyy")
                println(sdf.format(date))
                }   
            }
        }
    }
}

Date has the time as well, just add HH:mm:ss to the date format:

import java.text.SimpleDateFormat
def date = new Date()
def sdf = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss")
println sdf.format(date)

In case you are using JRE 8+ you can use LocalDateTime:

import java.time.LocalDateTime
def dt = LocalDateTime.now()
println dt