Townsend was born on August 7, 1943, in Cambridge, England, the second of three sons of Frederick and Nora Townsend. In 1957, his family moved to the United States and he attended Notre Dame High School in Elmira, New York. He then studied at Hobart College and graduated with a Bachelor of Arts in 1965. In 1968 he also graduated with a Master of Divinity from the Virginia Theological Seminary. Townsend was ordained deacon in 1968 and priest in 1969 by Bishop Ned Cole for the Diocese of Central New York. He the became assistant priest at St Paul's Cathedral in Syracuse, New York. Between 1971 and 1977, he became rector of St Christopher's Church in New Carrollton, Maryland. In 1987 he moved to Blacksburg, Virginia to serve as rector of Christ Church. Townsend was elected Coadjutor Bishop of Easton on June 11, 1992 on the third ballot of a special diocesan convention. He was consecrated on November 2l, 1992 in Salisbury, Maryland by Presiding Bishop Edmond L. Browning. He succeeded as diocesan bishop in 1993 and retired in 2001. Java ConcurrentMap  The Java programming language's Java Collections Framework version 1.5 and later defines and implements the original regular single-threaded Maps, and  also new thread-safe Maps implementing the interface among other concurrent interfaces. In Java 1.6, the ' interface was added, extending ', and the interface was added as a subinterface combination. The version 1.8 Map interface diagram has the shape below. Sets can be considered sub-cases of corresponding Maps in which the values are always a particular constant which can be ignored, although the Set API uses corresponding but differently named methods. At the bottom is the java.util.concurrent.ConcurrentNavigableMap, which is a multiple-inheritance. For unordered access as defined in the java.util.Map interface, the java.util.concurrent.ConcurrentHashMap implements java.util.concurrent.ConcurrentMap. The mechanism is a hash access to a hash table with lists of entries, each entry holding a key, a value, the hash, and a next reference. Previous to Java 8, there were multiple locks each serializing access to a 'segment' of the table. In Java 8, native synchronization is used on the heads of the lists themselves, and the lists can mutate into small trees when they threaten to grow too large due to unfortunate hash collisions.