Aims. We estimated the spectral evolution of white dwarfs with effective temperature using the Javalambre Photometric Local Universe Survey (J-PLUS) second data release (DR2), which provides 12 photometric optical passbands over 2176 deg 2 . Methods. We analyzed 5926 white dwarfs with r  ≤ 19.5 mag in common between a white dwarf catalog defined from Gaia EDR3 and J-PLUS DR2. We performed a Bayesian analysis by comparing the observed J-PLUS photometry with theoretical models of hydrogen- and helium-dominated atmospheres. We estimated the probability distribution functions for effective temperature ( T eff ), surface gravity, parallax, and composition; and the probability of having a H-dominated atmosphere ( p H ) for each source. We applied a prior in parallax, using Gaia EDR3 measurements as a reference, and derived a self-consistent prior for the atmospheric composition as a function of T eff . Results. We described the fraction of white dwarfs with a He-dominated atmosphere ( f He ) with a linear function of the effective temperature at 5000 <  T eff  < 30 000 K. We find f He  = 0.24 ± 0.01 at T eff  = 10 000 K, a change rate along the cooling sequence of 0.14 ± 0.02 per 10 kK, and a minimum He-dominated fraction of 0.08 ± 0.02 at the high-temperature end. We tested the obtained p H by comparison with spectroscopic classifications, finding that it is reliable. We estimated the mass distribution for the 351 sources with distance d  < 100 pc, mass M  > 0.45 M ⊙ , and T eff  > 6000 K. The result for H-dominated white dwarfs agrees with previous studies, with a dominant M  = 0.59 M ⊙ peak and the presence of an excess at M  ∼ 0.8 M ⊙ . This high-mass excess is absent in the He-dominated distribution, which presents a single peak. Conclusions. The J-PLUS optical data provide a reliable statistical classification of white dwarfs into H- and He-dominated atmospheres. We find a 21 ± 3% increase in the fraction of He-dominated white dwarfs from T eff  = 20 000 K to T eff  = 5000 K.