code: private void collectClauses() {
          assert this.level == 0;
          int i;
          int j = 0;
          long collected = 0;
          for (i = j; i < this.clauses.size(); i++) {
              if (i == this.distilled) { this.distilled = j; }
              final CLClause c = this.clauses.get(i);
              if (c.forcing() || !(c.dumped() || satisfied(c))) { this.clauses.set(j++, reduceClause(c)); } else {
                  deleteClause(c);
                  collected++;
              }
          }
          if (i == this.distilled) { this.distilled = j; }
          this.clauses.shrinkTo(j);
          this.stats.clausesCollected += collected;
      }
docs: Collect garbage (dumped) clauses.