eternal world record

QUESTION 

Why the Javelin World Record throw of Uwe Hohn (Germany) of 104.80 Mtrs. in 1984 is marked as "eternal world record". ?

ANSWER

Uwe Hohn of Germany is the only athlete to throw a Javelin more than 100 meters, with his World Record of 104.80 m in 1984

On 20 July 1984, competing in the Olympic Day of Athletics competition in Berlin 

1. Contrary to a popular myth however, this was not the primary reason for the change in javelin design rules that came into force starting in 1986 the relevant changes had already been officially proposed prior to Hohn's record throw, not only to shorten distances but even more to get rid of the then frequent flat or ambiguous landings, which often made it hard to assess if a throw should be declared legal
2. The record statistics therefore had to be restarted, and the mark of Uwe Hohn became an "eternal world record". The current world record under the new rules is Jan Zelezny's 98.48 m set in 1996.
3. On 1 April 1986, the men's javelin was redesigned by the governing body (the IAAF Technical Committee). They decided to change the rules for javelin design because of the increasingly frequent flat landings and the resulting discussions and protests when these attempts were declared valid or invalid by competition judges. The world record had also crept up to a potentially dangerous level, 104.80 m by Uwe Hohn . 
4. With throws exceeding 100 meters, it was becoming difficult to safely stage the competition within the confines of a stadium infield. The javelin was redesigned so that the centre of gravity was moved 4 cm (1.6 in) forward. In addition, the surface area in front of centre of gravity was reduced, while the surface area behind the centre of gravity was increased. This had the similar effect as feathers on an arrow. The javelin turns into the relative wind. 
5. This relative wind appears to originate from the ground as the javelin descends, thus the javelin turns to face the ground. As the javelin turns into the wind less lift is generated reducing the flight distance by around 10% but also causing the javelin to stick in the ground more consistently. In 1999, the women's javelin was similarly redesigned.