Galaxy clusters are the largest bounded structures in the Universe, which makes them perfect laboratories for studying cosmology and galaxy evolution. They host hundreds to thousand of galaxies divided in two populations: the red sequence, formed by early-type galaxies with no active star formation; and the blue cloud, composed of late-type, star-forming galaxies. Stellar Mass Functions (SMF) are a powerful way to know the properties of the galaxies of both populations, quiescent and star-forming ones. It can be computed as the number density of galaxies with respect to their stellar mass. We count galaxies in stellar mass bins and we correct from different biases and mass completeness. SMF also allows us to follow the evolution of the stellar formation rate (SFR) all along the cosmic time. SMF are also a fundamental to constraining cosmological simulations (see, e.g., Muzzin et al. 2013; van der Burg et al. 2020). In semi-analytic models, stellar mass functions represent a powerful tool to constrain parameters and also a great indicator to prove the predictions of the model. It is fundamental to compare the halo mass function from the simulation with the stellar mass function from the observational data. We analyze the abundance of star-forming and quiescent galaxies in the 3000 square degrees of public data J-PLUS Data Release 3 (DR3), over a redshift range 0.05 < z < 0.35. We compute diferent parameters by SED fitting with CIGALE as rest-frame colours: to separate between quiescent and star-forming galaxies; stellar masses: to compute the Stellar Mass Function. J-PLUS is being held at Observatorio Astrofísico de Javalambre (OAJ, Cenarro et al. 2014) using the 83 cm Javalambre Auxiliary Survey Telescope (JAST80) with a 9.2k x 9.2k pixel camera (public data) (T80Cam, Marin-Franch et al. 2015) reaching a 2deg2 field of view. The telescope is equipped with a set of 12 photometric filters, the five SDSS (ugriz) filters and seven medium or narrow-band filters. We aim at investigating the effect of the environment on the stellar mass function, SMF. The large area covered by JPLUS DR3 will enable environment to be defined using different proxies (cluster-centric distance, local galaxy density, and host halo-mass), allowing us to discern its effect on quenching and the physical mechanism at play (e.g., starvation, ram-pressure stripping).