Although not particularly observant, Mr. Kolomoysky, who is also the president of the United Jewish Community of Ukraine, has poured tens of millions of dollars into Jewish causes over the years. Together with a fellow billionaire, Gennadiy Bogolyubov, he financed the Menorah Center, the seven-towered, $70 million community center here where the veterans’ association, the Dnipropetrovsk Jewish Community and dozens of other organizations have their offices. Also housed in the building are the Israeli Consulate, a synagogue, kosher restaurants, a Shabbat-friendly hotel and a high-tech Holocaust museum.

The museum skirts the delicate issue of how some Ukrainian nationalists collaborated with the Nazis when Hitler invaded Ukraine in 1941, explaining instead how Jews supported Ukraine’s efforts to become an independent nation.

Before the Holocaust, Jews made up nearly a third of Dnipropetrovsk’s population, making it one of the most important centers of Jewish life and culture in Europe. The city now has 30,000 to 50,000 Jews, a small fraction of a total population of over a million but enough to sustain a vibrant community. The World Jewish Congress estimates that there are more than 250,000 Jews in Ukraine as a whole, the third-largest population of Jews among European nations.

“This is an example of a Jewish renaissance,” said Rabbi Kaminezki, a member of the Lubavitch movement who was born in Israel and studied at a rabbinical college in Morristown, N.J.

When protests against Mr. Yanukovych started in November, he said, many Jews shared the pro-European aspirations of the demonstrators who gathered in Kiev’s Independence Square, though some worried about the role played by far-right groups. One such group, Svoboda, stirred particular unease because of anti-Semitic remarks by its leaders in the past and its lionization of Ukrainian nationalist heroes who, in some cases, helped the Nazis and shared their ethnicity-based concept of nationhood.

But Rabbi Kaminezki said fears of a fascist revival had faded, “as there is a difference between what these people say to their own crowd and what they do when they become legitimate political leaders.” Anti-Semitism, he added, “exists in Ukraine, like everywhere,” but it has shown no sign of increasing since Mr. Yanukovych lost power.

After a series of unsolved anti-Semitic attacks since his ouster, including an assault on a rabbi and his wife in Kiev, the new head of Ukraine’s state security service told Jewish leaders that he would reopen a special unit to fight xenophobia and anti-Semitism that had been shut down under Mr. Yanukovych.