Answer to Question 1
John Rawls
Answer to Question 2
Common ethical dilemmas are having relatives involved in the cases, objectivity, affiliation with a case, appointment to committees or commissions that may have affiliations to cases, improper discussions or decisions, biases, and conflicts of interest.
There are several agencies that promulgate judicial ethics, like the American Judicature Society, the ABA's Model Code of Judicial Conduct, and the Judicial Conduct and Disability Act of 1980 are some.