I am a bit confused by your question. Firearms were not very common in Europe for some time-while matchlock arquebuses were certainly present and most countries had used some kind of gunpowder artillery, it took some time before personal firearms en masse were really "used" in a significant degree, most famously by de Cordoba at the Battle of Cerignola in 1503. Even then it took some time before the firearm became the primary weapon of infantry, as they reloaded slowly and were very vulnerable to heavy cavalry as was seen on numerous occasions well into even the 19th century. Pikes remained one of the main weapons of infantry, and the most successful tactical formations used pikes and arquebuses in tandem-the so-called "pike and shot"-of which one of the best known examples is the Spanish third, or tercio.

In comparison, the Japanese were introduced to the musket-which they knew as the tanegashima, named after the island where they first encountered it-a mere 40 years after the battle of Cerignola by Portuguese traders. It became common in Japanese armies shortly thereafter, especially after Japanese gunsmiths began to produce them en masse, such that by the time the Japanese attempted to invade Korea in the 1590s, they were able to put tens of thousands of gunners into the field.

It's worth adding that samurai were not a particular kind of equipped soldier but rather that they were a political class, analogous (but not exactly comparable) to that of the medieval knight. So samurai fought with many weapons, the most common being the yari (spear) and the yumi (bow) with the sword as a secondary close-quarter weapon. In fact, samurai were also armed with guns as well once they became available.