Many of the objections that people have had towards immigration in the past are similar to the ones that are heard nowadays. One of the most common one is the idea of immigrants "taking jobs away" from Americans. This was one of the reasons why California workers were against Japanese immigration.
Japanese people who arrived to California were very aware of the difficulties of making a new life in a new country, and because of this, they were willing to take bad jobs, tolerate abuse and work extremely hard. This made them successful. Many American laborers believed that the success of Japanese immigrants meant that there were less work, wealth or opportunities left for less successful Americans, particularly those who were not willing to tolerate the type of work Japanese immigrants did. This led to negative or hateful feelings towards the Japanese immigrants.