substring(x, from, len) - JPA CriteriaBuilder's method

Expression<String> substring(
  Expression<String> x,
  int from,
  int len

Create an expression for substring extraction. Extracts a substring of given length starting at the specified position. First position is 1.
x - string expression
from - start position
len - length
expression corresponding to substring extraction
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.