question: static OptimizedClassDescriptor classDescriptor ( ConcurrentMap < Class , OptimizedClassDescriptor > clsMap , int id , ClassLoader ldr , MarshallerContext ctx , OptimizedMarshallerIdMapper mapper ) throws IOException , ClassNotFoundException { Class cls ; try { cls = ctx . getClass ( id , ldr ) ; } catch ( IgniteCheckedException e ) { throw new IOException ( "Failed to resolve class for ID: " + id , e ) ; } OptimizedClassDescriptor desc = clsMap . get ( cls ) ; if ( desc == null ) { OptimizedClassDescriptor old = clsMap . putIfAbsent ( cls , desc = new OptimizedClassDescriptor ( cls , resolveTypeId ( cls . getName ( ) , mapper ) , clsMap , ctx , mapper ) ) ; if ( old != null ) desc = old ; } return desc ; }
target:  Gets descriptor for provided ID.