Barna’s father passed away when he was 10 years old. As a teenager, he learned to be an electrician.
His brother Tibor was taken to a labor camp in Hungary and later to the Ukraine. After the war, Barna learned that Tibor, with about 30-35 Hungarian Jews, was forced into a barn by Ukrainian and Hungarian Nazis. They poured gasoline onto the barn and everyone inside was burned to death. After the war, when Barna would wake, he would tell his wife that his first thoughts in the morning were about how his older brother died. His brother Laszlo fled to Russia and was in Siberia during the war. Gyula was in hiding in Budapest during the war. Barna survived Mauthausen concentration camp. Miklos also was in hiding in Budapest.
In 1942, Barna was taken to a labor camp in Budapest by Hungarian Nazis. In 1944, he was taken to Mauthausen concentration camp. At Mauthausen he worked in the forest cutting down trees. His feet were frozen; one foot almost had to be amputated. He described his experiences as being marked by suffering and starvation.
In 1953, in Hungary after the war, Barna changed his last name from Groszman to Havas because of antisemitism. His business was not doing well because he had a Jewish last name.