what is the similar of rxjs forkJoin operator in rxjava3

Question

I am trying to convert my fornt end code to java native code.But getting bit difficulty how to convert and what is similar operator which i can use in rxjava3.

Forntend rxjs example

createOrAlterTable$(dataType: string) {
    return forkJoin(this.readTableFromBackend$(dataType),
      this.readLastSyncFile$(), this.getUserData$())
      .pipe(switchMap(combineresult => {
        var sqlliteddl: any = combineresult[0];
        var lastfv: any = combineresult[1];
        var userDataFlag: any = combineresult[2];
        let obslist$ = [];
        ...
        ...
         let obseravel$ = this..createOrAlterTable(JSON.stringify(queryjson), type);
          obslist$.push(obseravel$);
        
        ...
        ...
        ...
        return forkJoin(obslist$);
      }));
  }

Same above i want to achieve in java 1.8 program using rxjava3. how?

Any help is very appriciated.

Thanks.