from(entityClass) - JPA AbstractQuery's method

Root<X> from(
  Class<X> entityClass

Create and add a query root corresponding to the given entity, forming a cartesian product with any existing roots.
entityClass - the entity class
query root corresponding to the given entity
JPA 2.0

This documentation page is derived (with some adjustments) from the open source JPA 2 RI (EclipseLink)
and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0.
Object Relational Mapping (ORM) JPA 2 providers include Hibernate, EclipseLink, TopLink, OpenJPA and DataNucleus.
ObjectDB is not an ORM JPA implementation but an Object Database for Java with built in JPA 2 support.