The situations referred to in the preceding paragraph include armed conflicts in which
peoples are fighting against colonial domination and alien occupation and against racist
régimes in the exercise of their right of self-determination, as enshrined in the Charter
of the United Nations and the Declaration on Principles of International Law concerning
Friendly Relations and Co-operation among States in accordance with the Charter of the
United Nations.”
The aim of paragraph 4 as quoted above seems to be to try to establish that certain armed conflicts that might be viewed by some as essentially internal in character, are really international, and hence fully subject to the better-developed legal regime governing international armed conflicts. As far as its specific reference to occupation is concerned, the paragraph does not concern itself directly with the definition or scope of ‘alien occupation’; and it adds little to the scope of application as spelt out in the 1949 Geneva Conventions themselves. All it really does is to close a tiny technical loophole in common Article 2, by making a little clearer what was already widely accepted – namely, that the law on occupations is applicable even in situations (like the West Bank and Gaza) where the occupied territory was not universally viewed as having been part of “the territory of a High Contracting Party.” As Bothe, Partsch and Solf say, it appears that the term ‘alien occupation’ is “meant to cover cases in which a High Contracting Party occupies territories of a State which is not a HCP, or territories with a controversial international status, and to establish that the population of such territory is fighting against the occupant in the exercise of their right of self-determination.”
http://www.icrc.org/eng/assets/files/publications/icrc-002-4094.pdf
From your link
the ICJ stated that occupation required the exercise of actual
authority by the foreign forces (emphasis added).5 In others words, the ICJ decided that foreign
troops should substantiate their authority in order to qualify as an occupying power.
Therefore, most of the experts supported a test based on the ability of enemy foreign forces to exert
authority over a specific area. As illustration, one expert referred to the situation of Denmark during
World War II when German armed forces, despite their military supremacy, had chosen not to exert
authority and had let the Danish Government do so instead.
Now isnt the P.A. in control of the west bank ?