question: public static boolean addLastCause ( @ Nullable Throwable e , @ Nullable Throwable cause , IgniteLogger log ) { if ( e == null || cause == null ) return false ; for ( Throwable t = e ; t != null ; t = t . getCause ( ) ) { if ( t == cause ) return false ; if ( t . getCause ( ) == null || t . getCause ( ) == t ) { try { t . initCause ( cause ) ; } catch ( IllegalStateException ignored ) { error ( log , "Failed to add cause to the end of cause chain (cause is printed here but will " + "not be propagated to callee): " + e , "Failed to add cause to the end of cause chain: " + e , cause ) ; } return true ; } } return false ; }
target:  Adds cause to the end of cause chain.