We report on $XMM-Newton$ EPIC observations of the young pulsar J2022+3842, with a characteristic age of 8.9 kyr. We detected X-ray pulsations and found the pulsation period $Papprox 48.6$ ms, and its derivative $dot{P}approx 8.6times 10^{-14}$, twice larger than the previously reported values. The pulsar exhibits two very narrow (FWHM $sim 1.2$ ms) X-ray pulses each rotation, separated by $approx 0.48$ of the period, with a pulsed fraction of $approx 0.8$. Using the correct values of $P$ and $dot{P}$, we calculate the pulsars spin-down power $dot{E}=3.0 times 10^{37}$ erg s$^{-1}$ and magnetic field $B=2.1times 10^{12}$ G. The pulsar spectrum is well modeled with a hard power-law (PL) model (photon index $Gamma = 0.9pm0.1 $, hydrogen column density $n_H = (2.3pm0.3) times 10^{22},{rm cm}^{-2}$). We detect a weak off-pulse emission which can be modeled with a softer PL ($Gamma approx 1.7pm0.7$), poorly constrained because of contamination in the EPIC-pn timing mode data. The pulsars X-ray efficiency in the $0.5-8$ keV energy band, $eta_{rm PSR}= L_{rm PSR}/dot{E} = 2 times 10^{-4} (D/10,{rm kpc})^2$, is similar to those of other pulsars. The $XMM-Newton$ observation did not detect extended emission around the pulsar. Our re-analysis of $Chandra$ X-ray observatory archival data shows a hard, $Gamma approx 0.9 pm 0.5$, spectrum and a low efficiency, $eta_{rm PWN}sim 2times 10^{-5} (D/10,{rm kpc})^2$, for the compact pulsar wind nebula, unresolved in the $XMM-Newton$ images.
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