This is a single-dose, single-center, open-label (all people know the identity of the intervention), 3-treatment, randomized (study medication assigned to participants by chance) and parallel-group (a medical research study comparing the response in two or more groups of participants receiving different interventions [treatments]) study. The study consists of Screening Phase (that is, 21 days before study commences on Day 1); open-label treatment Phase and end-of-study or early withdrawal assessment. All participants will be randomly assigned to 1 of 3 treatments, that is, Treatment A (single dose of JNJ-56021927 on Day 1), Treatment B (200 milligram [mg] itraconazole once daily from Day 1 up to Day 32 along with single dose of JNJ-56021927 on Day 4), and Treatment C (600 mg gemfibrozil twice daily from Day 1 up to Day 32 along with single dose of JNJ-56021927 on Day 4). Blood samples will be collected for evaluation of pharmacokinetics at pre-dose and post-dose of study treatment. The maximum duration of participation in the study per participant will be approximately 78 days (Treatment A) or 81 days (Treatment B and C). Participants' safety will be monitored throughout the study.