To calculate the population density for each country, we use the formula:

Population of Japan = 127,000,000
Total Land Mass of Japan = $378,000 \text{ km}^2$

$$\text{Population Density (Japan)} = \frac{127,000,000}{378,000 \text{ km}^2} \approx 335.98 \text{ people/km}^2$$

Population of India = 1,190,000,000
Total Land Mass of India = $3,170,000 \text{ km}^2$

$$\text{Population Density (India)} = \frac{1,190,000,000}{3,170,000 \text{ km}^2} \approx 375.39 \text{ people/km}^2$$

Population of Russia = 141,000,000
Total Land Mass of Russia = $17,100,000 \text{ km}^2$

$$\text{Population Density (Russia)} = \frac{141,000,000}{17,100,000 \text{ km}^2} \approx 8.25 \text{ people/km}^2$$

Population of Indonesia = 238,000,000
Total Land Mass of Indonesia = $1,900,000 \text{ km}^2$

$$\text{Population Density (Indonesia)} = \frac{238,000,000}{1,900,000 \text{ km}^2} \approx 125.26 \text{ people/km}^2$$

Population of Nigeria = 148,000,000
Total Land Mass of Nigeria = $923,768 \text{ km}^2$

$$\text{Population Density (Nigeria)} = \frac{148,000,000}{923,768 \text{ km}^2} \approx 160.21 \text{ people/km}^2$$

Here are the calculated population densities:

COUNTRY	POPULATION DENSITY (people/km$^2$)
Japan	335.98
India	375.39
Russia	8.25
Indonesia	125.26
Nigeria	160.21

The final answer is $\text{See table above}$.