Diabetes remains one of the health issues in Indonesia. The number of diabetes patients is increasing each year. The number of diabetes patients also impacts the use of diabetes medications, increasing the demand for diabetes drugs. Acarbose is commonly used to manage diabetes by inhibiting the α-glucosidase and α-amylase. However, acarbose has side effects such as diarrhea, abdominal bloating, and borborygmus. Therefore, an alternative with a similar mechanism to acarbose is needed. As reported that Java apple (Syzygium samarangense) has the potency to inhibit α-glucosidase and α-amylase. This study aimed to analyze the potency of the ethyl acetate extract of Java apple stem bark as an α-glucosidase and α-amylase inhibitor using an in silico approach. The types of α-glucosidase used are human maltase-glucoamylase (MGAM) and human pancreatic α-amylase (HPA) as α-amylase. From 61 compounds presented in S. samarangense ethyl acetate extract, 17 compounds showed good inhibition and docked at the same active site as acarbose (control drug), indicating that the compounds serve as α-glucosidase and α-amylase inhibitors. The binding affinity of these compounds ranges from -8.4 to -10.8 kcal/mol. Three compounds (epigallocatechin, isoengeletin, and kaempferol-3-O-rhamnoside) showed good drug-likeness and drug score value. The drug-likeness value is 0.31525, 1.8995, and 1.9289; the drug score value is 0.82, 0.79, and 0.77, respectively. The toxicity of these compounds was not detected. Therefore, epigallocatechin, isoengeletin, and kaempferol-3-O-rhamnoside are promising drug candidates.